Re: [time-nuts] On low-voltage TAC/TDCs for a GPSDO
J.D. Bakker wrote: At 08:30 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: 4) If the ADC(s) have a sufficiently wide full power bandwidth then one could just sample a pair of quadrature phased 250kHz sinewaves. As someone who's used to thinking in I/Q I must say I've always liked the elegance of this approach. Trouble is that I don't see a cheap/easy way to generate quadrature sines with low enough distortion/noise. Distortion isnt a great problem if its relatively small and stable as it can always be measured as part of the calibration process and its effect may then be compensated in software. Those are two large ifs, if you're going for a small/cheap implementation. Fully analog solutions can get messy, phase shifter hybrids are doable but would definitely need to be shielded from drafts and DDSes plus appropriate filters do the job but are still relatively expensive. And then there's motor/generators... Am I missing any method here? (on a semi-related note: some interesting work on ultralow distortion low frequency oscillators, employing quadrature signals to simplify the AGC, is being done here: http://www.prodigy-pro.com/diy/index.php?topic=26461.0) (I'm not sure why I'd want to use a synchronizer in this path. The way I see it the TAC operates as a linear phase detector, with the GPS PPS and the synthesized PPS as inputs. The microcontroller then applies the sawtooth correction to the measured time offset, and uses the result in a DPLL. There will, of course, be a synchronizer in the input line from the GPS PPS to the microcontroller, but that's only used for the FLL and for rough synchronization). Using a synchroniser allows the TAC output range to be combined with the coarse timestamp derived by sampling a counter clocked by the same clock as the synchroniser. I think we're looking at it from two different angles. What I read from your description is close to the traditional architecture such as used in the HP5335A, with a counter running at the system clock frequency for coarse measurement and a TAC to measure the remainder. What I'm planning to do is more akin a traditional PLL, with the TAC as the Phase Detector. For this to work I assume that a coarse FLL (using a counter) has already brought the oscillator within lock range. Is there any reason that method won't work, or can trivially be made to work better? Having a wide TAC range means that its resolution and noise depends critically on that of the ADC. Since some ADCs embeded within processor dont have true 12 bit performance this may limit the TAC resolution/noise to several nanosec rather than the desired 1ns or better. (The regenerated PPS output will indeed be derived from and synchronous with the VCXO/OCXO. It is also my intention to have the OCXO clock the microcontroller, either directly or through a prescaler, depending on whether the XO runs higher or lower than the max CPU clock). That ensures that all intermod products are harmonically or submultiples of the OCXO frequency. - Circuit 3 expands on this approach by having dual ramp generators, and having the ADC measure the voltage difference between the two. Not a good idea, as this requires accurate matching of the gains of the 2 TACs. Why? At that points they're not TACs yet, just ramp generators. Circuit 3 uses the difference between these ramps, and I believe it need not be constant. Assume there's a 1% difference in ramp rates; say C3 charges at 1V/us and C4 charges at 1.01V/us. [...] Since NP0/C0G caps are only available in 5% and 10% tolerance at best, matching gains to 1% will require using selected parts (adjust current source to compensate) or trimming. I picked the 1% figure out of the air, simply to have an example for the math. Even so, if required it would be easy to have the microcontroller trim the ramp rates through one of the on-chip DACs. However I don't believe that the ramp rate can't be dealt with in software through calibration. Software is probably best (if feasible) as this eliminates the parasitic capacitances and noise associated with trimmers and DACs. With a single ADC its not possible to correct the TAC nonlinearity since there are a wide range of possible output voltages from the first TAC for any given differential input to the ADC. Simulation indicates nonlinearity of the order of 1% or so in the ramp generator. This is largely due to the Early effect and semiconductor output capacitance modulation. Yeah, I noticed that. It helps a lot in the four-transistor mirror to have all transistors carry approximately equal amounts of current. Further linearization can be achieved by increasing the current, slowing the ramp rate and picking transistors with lower hFE for a given fT and/or higher VAF. An output resistance of up to 1M can be achieved, but it's the voltage-dependent capacitance that's hurting linearity. Lower hfe requires tighter
[time-nuts] PICTIC II PIC chips, update and opening for more orders
Hi guys, My project is over and I'll be home on Sunday. The chips that were ordered and paid for will go out tomorrow and you should see them this coming week. I know some of you are itchy to get chips ordered and I apologize for dropping off the grid these past three weeks. I've been on travel for work and have put in some crazy hours. To jump start things, I'll start taking orders for the next round of chips instead of waiting till Monday. I learned some lessons from the first time around. The main lesson was that a week was not long enough to wait for orders to come in before placing my order for the PIC chips. I had more requests after I placed the order to Mouser than I did the week before while I was taking orders. This time I'll close for orders on 8/29 at noon (mountain time) and will place the order with Mouser or Digikey. I'll get them shipped out to you a few days after they arrive. The other thing I learned was that doing this in email with gmail is somewhat problematic. I won't go into details, but labels in gmail are NOT the same as folders even if they look like them at first glance. If you want a programmed PIC chip, just send payment with PayPal before noon (again, mountain time) on 8/29/2010 and make sure you include a valid shipping address. Of course I'm perfectly happy to answer questions in email, I just don't want to deal with keeping track of orders with email. Digging through email to get shipping info wasn't as easy as it should be. Details: The first chip costs $10.00 including shipping to the continental US (CONUS). Each additional chip costs $2.50, including shipping. All chips will be sent in an anti-static tube inside of a padded envelope: 1 PIC - $10.00 shipped 2 PICs - $12.50 shipped 3 PICs - $15.00 and so on. Please send payment to rdarling...@gmail.com and again, make sure you include a valid shipping address inside of the continental US. No need to email me first. Another option if you can't wait is to order chips from your vendor of choice and have them shipped directly to me. I will ship them to you at cost. No charge for programming since it's not my code and electrons are pretty cheap these days. Contact me directly and I'll be happy to send you my home address if you want to do it this way. Once we get through this round of orders I'll be happy to offer reprogramming services for the cost of shipping should a firmware update come out. Thanks guys, -Bob, N3XKB ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] On low-voltage TAC/TDCs for a GPSDO
At 19:01 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: At 08:30 +1200 14-08-2010, Bruce Griffiths wrote: Using a synchroniser allows the TAC output range to be combined with the coarse timestamp derived by sampling a counter clocked by the same clock as the synchroniser. I think we're looking at it from two different angles. What I read from your description is close to the traditional architecture such as used in the HP5335A, with a counter running at the system clock frequency for coarse measurement and a TAC to measure the remainder. What I'm planning to do is more akin a traditional PLL, with the TAC as the Phase Detector. For this to work I assume that a coarse FLL (using a counter) has already brought the oscillator within lock range. Is there any reason that method won't work, or can trivially be made to work better? Having a wide TAC range means that its resolution and noise depends critically on that of the ADC. Since some ADCs embeded within processor dont have true 12 bit performance this may limit the TAC resolution/noise to several nanosec rather than the desired 1ns or better. No, the TAC range would only be wide enough to cover the expected spread of valid PPS pulses from the GPS (say +/-500ns...+/-1us). (I've thought a bit more about what you proposed, ie using the TAC to measure synchronizer delay. Problem is I'd like to use the timestamping counter that's internal to the CPU, and I see no way of getting at the output of its built-in synchronizer. This could of course be fixed by using an external timestamping counter/synchronizer, but that seems like a bit of a waste of resources). (The regenerated PPS output will indeed be derived from and synchronous with the VCXO/OCXO. It is also my intention to have the OCXO clock the microcontroller, either directly or through a prescaler, depending on whether the XO runs higher or lower than the max CPU clock). That ensures that all intermod products are harmonically or submultiples of the OCXO frequency. Indeed. I prefer knowing where my birdies are (and preferably placing them where they do the least harm), rather than having them drift over time, frequency and temperature. The output compliance of your four transistor current mirror is limited to around 1.3V or so before the onset of saturation or gross nonlinearity. It's actually better than that, from what I can see from simulations and measurements. If the transistor currents are close to equal and the ramp rate isn't too high, output current stays within 1% up to ~1V, and the mirror saturates at 0.6-0.7V. This is with common small-signal transistors with an fT of a few hundred MHz. Really? There are 2xVbe + 1x diode drop to subtract from 3.3V ie somewhere from 1.8V -2.4V leaving a ramp amplitude of 1.5V to 1.1V depending on temperature and transistor current. That's what I thought when I first saw it and started counting junctions, but it's actually quite a bit better than that as the cross-coupling of the transistors steers current from saturating transistors into the bases of the opposing CE transistor. I found it in Barrie Gilbert's chapter on Bipolar Current Mirrors in the book Analogue IC Design: the current-mode approach; Google Books has a preview of much of this chapter. I've tried it in the simulator and on the bench, and it works quite well. If you want to test it I suggest increasing the current source to 10mA, the cap to 10nF and starting with 150R for R1/R2 plus 10R emitter resistors for the CE transistors. I've tested it with the common European BC5xx/BC8xx-types, but LTSpice seems to like it with 2N3906s too. In that configuration, the ramp stays within +/-150uV of a linear approximation over a ramp range between 0 and 2V when ramping at 1V/us, which corresponds to +/-0.6LSB for a 12-bit ADC. [I should probably make a sketch of the entire GPSDO and post it] Yes that would be useful as details can often be important. I have to leave now, will do so when I get back. Thanks, JDB. -- Years from now, if you are doing something quick and dirty, you imagine that I am looking over your shoulder and say to yourself, Dijkstra would not like this, well that would be immortality for me. -- Edsger Dijkstra, 1930 - 2002 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] On low-voltage TAC/TDCs for a GPSDO
J.D. Bakker wrote: At 19:01 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: At 08:30 +1200 14-08-2010, Bruce Griffiths wrote: Using a synchroniser allows the TAC output range to be combined with the coarse timestamp derived by sampling a counter clocked by the same clock as the synchroniser. I think we're looking at it from two different angles. What I read from your description is close to the traditional architecture such as used in the HP5335A, with a counter running at the system clock frequency for coarse measurement and a TAC to measure the remainder. What I'm planning to do is more akin a traditional PLL, with the TAC as the Phase Detector. For this to work I assume that a coarse FLL (using a counter) has already brought the oscillator within lock range. Is there any reason that method won't work, or can trivially be made to work better? Having a wide TAC range means that its resolution and noise depends critically on that of the ADC. Since some ADCs embeded within processor dont have true 12 bit performance this may limit the TAC resolution/noise to several nanosec rather than the desired 1ns or better. No, the TAC range would only be wide enough to cover the expected spread of valid PPS pulses from the GPS (say +/-500ns...+/-1us). With some internal 12 bit ADCs that dont have true 12 bit you will barely achieve 1ns resolution with a 2us range. (I've thought a bit more about what you proposed, ie using the TAC to measure synchronizer delay. Problem is I'd like to use the timestamping counter that's internal to the CPU, and I see no way of getting at the output of its built-in synchronizer. This could of course be fixed by using an external timestamping counter/synchronizer, but that seems like a bit of a waste of resources). Surely you only need an external synchroniser (ie a dual D flipflop) clocked by the same clock (or at least one synchronous with it) as the internal counter? The internal synchroniser then only adds a fixed delay. (The regenerated PPS output will indeed be derived from and synchronous with the VCXO/OCXO. It is also my intention to have the OCXO clock the microcontroller, either directly or through a prescaler, depending on whether the XO runs higher or lower than the max CPU clock). That ensures that all intermod products are harmonically or submultiples of the OCXO frequency. Indeed. I prefer knowing where my birdies are (and preferably placing them where they do the least harm), rather than having them drift over time, frequency and temperature. The output compliance of your four transistor current mirror is limited to around 1.3V or so before the onset of saturation or gross nonlinearity. It's actually better than that, from what I can see from simulations and measurements. If the transistor currents are close to equal and the ramp rate isn't too high, output current stays within 1% up to ~1V, and the mirror saturates at 0.6-0.7V. This is with common small-signal transistors with an fT of a few hundred MHz. Really? There are 2xVbe + 1x diode drop to subtract from 3.3V ie somewhere from 1.8V -2.4V leaving a ramp amplitude of 1.5V to 1.1V depending on temperature and transistor current. That's what I thought when I first saw it and started counting junctions, but it's actually quite a bit better than that as the cross-coupling of the transistors steers current from saturating transistors into the bases of the opposing CE transistor. I found it in Barrie Gilbert's chapter on Bipolar Current Mirrors in the book Analogue IC Design: the current-mode approach; Google Books has a preview of much of this chapter. Simulation appears to indicate otherwise, distortion starts to rise as one of the mirror transistors nears saturation. One way to look at this is to look at variations in ramp charging current. However the ultimate test (other than breadboarding it) is to actually simulate the sampling process and look at the deviation of the sampled voltages from linearity. In the case of the 3 diode TAC devised by Kasper Pedersen some compensation of diode capacitance modulation occurs if the diodes are matched. I've tried it in the simulator and on the bench, and it works quite well. If you want to test it I suggest increasing the current source to 10mA, the cap to 10nF and starting with 150R for R1/R2 plus 10R emitter resistors for the CE transistors. I've tested it with the common European BC5xx/BC8xx-types, but LTSpice seems to like it with 2N3906s too. In that configuration, the ramp stays within +/-150uV of a linear approximation over a ramp range between 0 and 2V when ramping at 1V/us, which corresponds to +/-0.6LSB for a 12-bit ADC. I'll check again, but thats not consistent with what I found with a simulated 1mA current source. The capacitor charging current started to deviate significantly as saturation was approached. I also simulated other current sources with higher
Re: [time-nuts] What's the latest correct PICTIC II Mouser project?- Heathkid
Hi This isn't my design originally. The 620 ohm resistor in question sources current into a diode stack. The initial current will vary more from the tolerance of the diodes than it will from the 1 ohm change ( or 6 ohm = 1%). The other resistor sets the range on two pots. The pot's tolerance is = 5x the resistor's. The new value will give you slightly more adjustment range in some cases. The simple answer really is that the values for 5% and 1% resistors are different. This being the world that it is, you can get 1%'s in 5% values. I switched systems to find available parts. The other simple answer is that the accuracy of the design comes more from pot twiddling than from initial resistor values. Bob On Aug 13, 2010, at 11:34 PM, Heathkid heath...@heathkid.com wrote: Bob, Thanks for the update! How critical are the values of the components? If I'm going to build this (actually six of them)... I'd prefer to do it right (and best) the first time. Going from a 620ohm 1% to a 619ohm is probably negligible. But if it's design is *supposed* to require a 620ohm 1% 50ppm metal film resistor then shouldn't that be what I should get (even if I have to get it from a different source)? Maybe I'm being *really* picky here... I do tend to take things to **extremes**. Even the people I work with get frustrated sometimes with me because when I build things... I tend to match resistors, caps, inductors, etc. to within 0.001% of what the design specifies. Yes... I've bought 400 resistors for a headphone amplifier just to find two that were matched perfectly (even at temperature changes - 0C to 40C). Also, when building... can the standard IC's be socketed - I like it that way (I'm sure the PIC is okay)? I know that affects some circuits. Do you know if this will have any effect on the operation or accuracy of the PICTIC II? If it's okay... standard or machine pin (if it makes a difference). And finally... *what* should the input/output connectors be? Thanks again! 73 Brice KA8MAV - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, August 13, 2010 5:34 PM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouser project?- Heathkid Hi Shortages... what shortages :)..? The two offending resistors have been bumped to 1% standard values from 5% standard. Functionally there should be no difference at all. Sorry for the delay in getting it up dated. Bob On Aug 13, 2010, at 1:47 AM, Heathkid wrote: Hello everyone. I received my six (6) PICTIC II PCBs which are absolutely beautiful (after a couple minutes of standard cleaning with a pencil eraser which I do anyway to *any* PCB* I order) and I was getting ready to place my order for the components tonight but the following (in the latest project) are now back ordered with estimated shipping dates of like October! Any suggestions for equal or superior parts? Please? Does anyone have an updated Mouser Project that has all the correct or better quality parts in stock (equal to or better quality that spec'd)? Here's what I've been trying to work with thanks to Bob Camp. Unfortunately, two of the components are now not available... help??? https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=8736DCEE10 Mouser #: 271-620-RC Metal Film Resistors - Through Hole 620ohms 1% 50PPM Mouser #: 271-2.4K-RC Metal Film Resistors - Through Hole 2.4Kohms 1% 50PPM I'd like to place the complete order for all the components for my six PICTIC II's as quickly as possiible. Thanks, 73 Brice KA8MAV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Simulation
Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I have ALWAYS distrusted simulation and computer modeling. And I used to teach the stuff. GIGO. Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon -John === Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What's the latest correct PICTIC II Mouser project?- Heathkid
From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 7:05:35 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouser project?- Heathkid Hi This isn't my design originally. The 620 ohm resistor in question sources current into a diode stack. The initial current will vary more from the tolerance of the diodes than it will from the 1 ohm change ( or 6 ohm = 1%). snip Maybe we should buy lots of diodes to match them, they are relative cheap, also use extra care installing them. Using hemostats as heat sinks and just enough heat for a good connection do not want to damage/change them after the match. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Bob Camp wrote: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. there are also designs that depend on non-data-sheet performance of particular devices. There's a very low noise, very low leakage fet popular in charge amplifiers. It has a JEDEC 2N number (which I can't remember off hand), but only the ones from one particular company (in England) actually work in the circuits, and even then, there's some hand selection involved. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John === Bob Camp wrote: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. there are also designs that depend on non-data-sheet performance of particular devices. There's a very low noise, very low leakage fet popular in charge amplifiers. It has a JEDEC 2N number (which I can't remember off hand), but only the ones from one particular company (in England) actually work in the circuits, and even then, there's some hand selection involved. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Actually this is a good argument FOR modeling well applied because you can simulate parts that you cannot buy today but that your vendor will ship under the same part number a few years down the road. Try doing that in the lab... I have experienced it so many times it's not even funny. And that includes parts bought against SMD (Standard Military Drawings) which tend to have more complete specs than the commercial parts they target. Another area is simulating the effects or radiations. Quite expensive to do in practice, when it's even practical. On the other hand, if the model does not work like the hardware, don't look for what's wrong with the hardware :) Always get the model to work like the hardware before you make changes. Didier Famous last words: But the prototype worked so well. Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Bob Camp li...@rtty.us Sender: time-nuts-boun...@febo.com Date: Sat, 14 Aug 2010 08:30:29 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Simulation Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
(in production yes I agree) In research things are different. You wouldn't mind to make an selection of fets or else to obtain the very top specs of a certain unique instrument design as the real final product are the results you may obtain with that instrument and not at all it's design... So many nice stories about gear that worked only with a certain set of parts way off the manufacturers expressed data... one day I'll drop a few here just for amusement. Luis Cupido ct1dmk. J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John === Bob Camp wrote: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. there are also designs that depend on non-data-sheet performance of particular devices. There's a very low noise, very low leakage fet popular in charge amplifiers. It has a JEDEC 2N number (which I can't remember off hand), but only the ones from one particular company (in England) actually work in the circuits, and even then, there's some hand selection involved. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid
Okay Stanley... I've got a Tektronix 370A curve tracer at work. So the diodes need to be matched? No problem. So I match the diodes and the resistors to within 0.001%. Are there any other components that need matched? Also, you mentioned using hemostats as heatsinks on the diodes while installing them. I know that diodes make very good temperature sensors as well. Are there any suggestions on keeping them stable after they are on the board? What is the recommended operating temperature of the PICTIC II? Thanks. 73 Brice KA8MAV - Original Message - From: Stanley Reynolds stanley_reyno...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, August 14, 2010 10:43 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid snip Maybe we should buy lots of diodes to match them, they are relative cheap, also use extra care installing them. Using hemostats as heat sinks and just enough heat for a good connection do not want to damage/change them after the match. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John Or, has their back against the wall and can't do it any other way. How is this any different than using trimpots or hand select? For years, folks have hand selected matched pairs of devices, since the circuit requires tighter tolerances than the mfr guarantees. Many, many RF designs have select at test pads to set levels or tuning stubs depending on what the actual gain or impedance properties of the active devices are, or for trimming temperature dependencies. Would you say that the engineer is a fool for not just specifying tighter tolerances.. the tighter tolerances may not be available from the mfr (who has to respond to many customers, most of which will be happy with the standard performance). It's sort of a tradeoff.. do you go to the mfr and say, I need a better grade of part, or do you buy the run-of-the-mill part, and sort them. You might decide to do the latter for competitive reasons, e.g. rather than the mfr producing a better grade of part, and potentially selling it to your competitors too, you keep the secret sauce in house. (Granted you could have the mfr make/select a proprietary part for you.. that's basically changing who does the work, but doesn't change the underlying design) Even manufacturers do this, for instance with speed grades on things like microprocessors. They don't have enough process control to guarantee a particular speed, so they make em all, and then sort them. The other thing is that the selection criteria might not be knowable in a standalone sense. That is, you have to put the part into the circuit and see if it works, rather than measuring some device parameter. I would agree that to a certain extent, this implies that you don't really know how the circuit works, but it might also be that the most cost effective approach is to use empiricism, rather than analysis. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Simulation has some value in determining things like allowable component tolerances and Worst Case analysis, but those are really production engineering rather than design. As to working at brassboard but not in production, it is prudent to check that your parts are within the production part specs. John === (in production yes I agree) In research things are different. You wouldn't mind to make an selection of fets or else to obtain the very top specs of a certain unique instrument design as the real final product are the results you may obtain with that instrument and not at all it's design... So many nice stories about gear that worked only with a certain set of parts way off the manufacturers expressed data... one day I'll drop a few here just for amusement. Luis Cupido ct1dmk. J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John === Bob Camp wrote: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. there are also designs that depend on non-data-sheet performance of particular devices. There's a very low noise, very low leakage fet popular in charge amplifiers. It has a JEDEC 2N number (which I can't remember off hand), but only the ones from one particular company (in England) actually work in the circuits, and even then, there's some hand selection involved. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I think you missinterpret what I meant. Two examples: I've seen programmers who use instructions that are not part of a uP instruction set and are undocumented, just to be clever. If a different brand of chip, or even a different rev., the chip does something completely different. These guys should be strung up by their tender parts. I've also seen transistors used as avalanche switches (basically a failure mode). If a different production run has improved normal mode performance, the avalanche function may vanish. FWIW, -John === J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John Or, has their back against the wall and can't do it any other way. How is this any different than using trimpots or hand select? For years, folks have hand selected matched pairs of devices, since the circuit requires tighter tolerances than the mfr guarantees. Many, many RF designs have select at test pads to set levels or tuning stubs depending on what the actual gain or impedance properties of the active devices are, or for trimming temperature dependencies. Would you say that the engineer is a fool for not just specifying tighter tolerances.. the tighter tolerances may not be available from the mfr (who has to respond to many customers, most of which will be happy with the standard performance). It's sort of a tradeoff.. do you go to the mfr and say, I need a better grade of part, or do you buy the run-of-the-mill part, and sort them. You might decide to do the latter for competitive reasons, e.g. rather than the mfr producing a better grade of part, and potentially selling it to your competitors too, you keep the secret sauce in house. (Granted you could have the mfr make/select a proprietary part for you.. that's basically changing who does the work, but doesn't change the underlying design) Even manufacturers do this, for instance with speed grades on things like microprocessors. They don't have enough process control to guarantee a particular speed, so they make em all, and then sort them. The other thing is that the selection criteria might not be knowable in a standalone sense. That is, you have to put the part into the circuit and see if it works, rather than measuring some device parameter. I would agree that to a certain extent, this implies that you don't really know how the circuit works, but it might also be that the most cost effective approach is to use empiricism, rather than analysis. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi The PDP-8 had so much code that depended on un-documented instructions that they had to include them in later versions of the machine Bob On Aug 14, 2010, at 12:01 PM, J. Forster j...@quik.com wrote: I think you missinterpret what I meant. Two examples: I've seen programmers who use instructions that are not part of a uP instruction set and are undocumented, just to be clever. If a different brand of chip, or even a different rev., the chip does something completely different. These guys should be strung up by their tender parts. I've also seen transistors used as avalanche switches (basically a failure mode). If a different production run has improved normal mode performance, the avalanche function may vanish. FWIW, -John === J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John Or, has their back against the wall and can't do it any other way. How is this any different than using trimpots or hand select? For years, folks have hand selected matched pairs of devices, since the circuit requires tighter tolerances than the mfr guarantees. Many, many RF designs have select at test pads to set levels or tuning stubs depending on what the actual gain or impedance properties of the active devices are, or for trimming temperature dependencies. Would you say that the engineer is a fool for not just specifying tighter tolerances.. the tighter tolerances may not be available from the mfr (who has to respond to many customers, most of which will be happy with the standard performance). It's sort of a tradeoff.. do you go to the mfr and say, I need a better grade of part, or do you buy the run-of-the-mill part, and sort them. You might decide to do the latter for competitive reasons, e.g. rather than the mfr producing a better grade of part, and potentially selling it to your competitors too, you keep the secret sauce in house. (Granted you could have the mfr make/select a proprietary part for you.. that's basically changing who does the work, but doesn't change the underlying design) Even manufacturers do this, for instance with speed grades on things like microprocessors. They don't have enough process control to guarantee a particular speed, so they make em all, and then sort them. The other thing is that the selection criteria might not be knowable in a standalone sense. That is, you have to put the part into the circuit and see if it works, rather than measuring some device parameter. I would agree that to a certain extent, this implies that you don't really know how the circuit works, but it might also be that the most cost effective approach is to use empiricism, rather than analysis. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
DEC code was a nightmare. Any DG Nova line code would run on any machine. -John = Hi The PDP-8 had so much code that depended on un-documented instructions that they had to include them in later versions of the machine Bob On Aug 14, 2010, at 12:01 PM, J. Forster j...@quik.com wrote: I think you missinterpret what I meant. Two examples: I've seen programmers who use instructions that are not part of a uP instruction set and are undocumented, just to be clever. If a different brand of chip, or even a different rev., the chip does something completely different. These guys should be strung up by their tender parts. I've also seen transistors used as avalanche switches (basically a failure mode). If a different production run has improved normal mode performance, the avalanche function may vanish. FWIW, -John === J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John Or, has their back against the wall and can't do it any other way. How is this any different than using trimpots or hand select? For years, folks have hand selected matched pairs of devices, since the circuit requires tighter tolerances than the mfr guarantees. Many, many RF designs have select at test pads to set levels or tuning stubs depending on what the actual gain or impedance properties of the active devices are, or for trimming temperature dependencies. Would you say that the engineer is a fool for not just specifying tighter tolerances.. the tighter tolerances may not be available from the mfr (who has to respond to many customers, most of which will be happy with the standard performance). It's sort of a tradeoff.. do you go to the mfr and say, I need a better grade of part, or do you buy the run-of-the-mill part, and sort them. You might decide to do the latter for competitive reasons, e.g. rather than the mfr producing a better grade of part, and potentially selling it to your competitors too, you keep the secret sauce in house. (Granted you could have the mfr make/select a proprietary part for you.. that's basically changing who does the work, but doesn't change the underlying design) Even manufacturers do this, for instance with speed grades on things like microprocessors. They don't have enough process control to guarantee a particular speed, so they make em all, and then sort them. The other thing is that the selection criteria might not be knowable in a standalone sense. That is, you have to put the part into the circuit and see if it works, rather than measuring some device parameter. I would agree that to a certain extent, this implies that you don't really know how the circuit works, but it might also be that the most cost effective approach is to use empiricism, rather than analysis. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 08/14/2010 05:48 PM, J. Forster wrote: Simulation has some value in determining things like allowable component tolerances and Worst Case analysis, but those are really production engineering rather than design. As to working at brassboard but not in production, it is prudent to check that your parts are within the production part specs. Simulation as such is a very useful tool. Propper use may save time, misuse will cost you big-time. It does not replace breadboarding and design verification, but may speed up design and what if? on failure mode testing. I've often found that proposing a solution and have a quick simulation has helped in convincing on certain design ideas. In particular some designer make things more complex than they need to be... but a quick simulation gets them on the right track. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 08/14/2010 06:15 PM, J. Forster wrote: DEC code was a nightmare. Any DG Nova line code would run on any machine. This is how we have learned what is a bad idea... and it is now documented in the guidelines. Use of the top 8 bits in pointers caused headaches for the 68k machines when they needed more than 16 MB of addressing. Amongst other things. The undocumented features of the 6502 is now being maintained in modernized versions... maybe a better choice in design could be made. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hello, I've read at least two similar stories in Troubleshooting Analog Circuits by Bob Pease. One is that it seems that some time ago, National Semiconductor started shipping LF411s marked as LF351s as an improvement... and as Bob says, most of the customers probably were happy with that (I think that most of them probably never noticed the change), but the gain on the trim circuit was reversed (in the LF351, if you turn the trim pot in one way, Vos increases - in the LF411, turning it in the same way makes Vos to decrease), and this probably would have made some people not so happy with the improvement :) Another story is about 2N3771 transistor, initially a single-diffussed part, but later an epitaxial base part - with a lot more gain bandwidth product. But since the 'new' 2N3771 meets and exceeds original 2N3771 specs, the same part number was used - but the part is quite different (and published specs continues being the JEDEC ones). So you can imagine that in some applications it would be quite a lot of difference if you breadboard with the older, and during the manufacturing phase you (probably without knowing it) switch to the new part. I suffered some time ago a change in a small DSP from Freescale. It is a 3.3V part with 5V tolerant I/O, and I assumed (not sure if this was in the datasheet or not) that reset pin was also 5V tolerant. Prototypes worked, and production worked, but after 2-3 years of production, and from some DSP production date code, we experienced a problem with the part reset - the part did no longer liked the 5V level at the reset pin. I asked Freescale about any change, but never got any response. I periodically receive PCNs (product change notifications) from EBV Elektronik, which is a quite big european semiconductor distributor, whenever some product that I'm purchasing or have purchased in the past suffers some manufacturing change (manufacturing moved to other plant, process change, case materials change, etc...), like for example this one: http://www.ebv.com/fileadmin/templates/scripts/pcn/data/200907002f__1248209503.pdf But I suppose that not all manufacturers are so kind to let the customers know in advance these kind of things :) Best regards, Javier El 14/08/2010 14:30, Bob Camp escribió: Hi Simply a few stories I thought I would share. Simulate design. Use manufacturer's published models. Build design. Note differences. Call manufacturer. Answer - switched die three years ago, Ft is now much better ( now 3x old parts ). Odd they never mentioned that to people who work for the same company. Simulate design, Build design, verify design, ship it for a few years. Odd things start to happen. Look at some parts. Package looks different. Ask around. Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. Again all inside the same company. Both cases were excused by industry standard specs that had no upper limit. We had whole departments devoted to tracking this sort of stuff. It still happened on a regular basis. 30 years later the specs on the devices and their published models are still the old version ones. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid
1) I have no previous experience building precision anything, I'm not an expert. 2) My guess is the design expects quality components and depends on the auto calibration to correct any component drift. Short term stability between calibrations is what we want. The absolute value of C16 and C17 is not as important as it's stability in leakage and value. Guess we could put the didoes in a constant temp oven but not sure all the components are more stable at higher temps. Good ideas about didoes here : http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p033.shtml (note Figure 3 and how the didoes voltage drop is more linear at higher temps vs room temp.) Figure 3. Stanley From: Heathkid heath...@heathkid.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:43:15 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid Okay Stanley... I've got a Tektronix 370A curve tracer at work. So the diodes need to be matched? No problem. So I match the diodes and the resistors to within 0.001%. Are there any other components that need matched? Also, you mentioned using hemostats as heatsinks on the diodes while installing them. I know that diodes make very good temperature sensors as well. Are there any suggestions on keeping them stable after they are on the board? What is the recommended operating temperature of the PICTIC II? Thanks. 73 Brice KA8MAV - Original Message - From: Stanley Reynolds stanley_reyno...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, August 14, 2010 10:43 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid snip Maybe we should buy lots of diodes to match them, they are relative cheap, also use extra care installing them. Using hemostats as heat sinks and just enough heat for a good connection do not want to damage/change them after the match. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. attachment: Capture.JPG___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 08/14/2010 06:39 PM, Javier Herrero wrote: Hello, I've read at least two similar stories in Troubleshooting Analog Circuits by Bob Pease. One is that it seems that some time ago, National Semiconductor started shipping LF411s marked as LF351s as an improvement... and as Bob says, most of the customers probably were happy with that (I think that most of them probably never noticed the change), but the gain on the trim circuit was reversed (in the LF351, if you turn the trim pot in one way, Vos increases - in the LF411, turning it in the same way makes Vos to decrease), and this probably would have made some people not so happy with the improvement :) Another story is about 2N3771 transistor, initially a single-diffussed part, but later an epitaxial base part - with a lot more gain bandwidth product. But since the 'new' 2N3771 meets and exceeds original 2N3771 specs, the same part number was used - but the part is quite different (and published specs continues being the JEDEC ones). So you can imagine that in some applications it would be quite a lot of difference if you breadboard with the older, and during the manufacturing phase you (probably without knowing it) switch to the new part. One side-effect is that you run into possibilities of oscillation. This have happend and was the cause of a GPS outage in a US Harbour a few years back. What was a wise design became an enemy due to a subtle change in part. Don't recall if the part was replaced by an equivalent or same part-number, but the new version didn't work as expected during all conditions... Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Fw: What's the latest correct PICTIC II Mouserproject?- Heathkid
Duplicate message without in-line picture. - Forwarded Message From: Stanley Reynolds stanley_reyno...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 11:41:36 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid 1) I have no previous experience building precision anything, I'm not an expert. 2) My guess is the design expects quality components and depends on the auto calibration to correct any component drift. Short term stability between calibrations is what we want. The absolute value of C16 and C17 is not as important as it's stability in leakage and value. Guess we could put the didoes in a constant temp oven but not sure all the components are more stable at higher temps. Good ideas about didoes here : http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p033.shtml (note Figure 3 and how the didoes voltage drop is more linear at higher temps vs room temp.) Stanley From: Heathkid heath...@heathkid.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:43:15 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid Okay Stanley... I've got a Tektronix 370A curve tracer at work. So the diodes need to be matched? No problem. So I match the diodes and the resistors to within 0.001%. Are there any other components that need matched? Also, you mentioned using hemostats as heatsinks on the diodes while installing them. I know that diodes make very good temperature sensors as well. Are there any suggestions on keeping them stable after they are on the board? What is the recommended operating temperature of the PICTIC II? Thanks. 73 Brice KA8MAV - Original Message - From: Stanley Reynolds stanley_reyno...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, August 14, 2010 10:43 AM Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?- Heathkid snip Maybe we should buy lots of diodes to match them, they are relative cheap, also use extra care installing them. Using hemostats as heat sinks and just enough heat for a good connection do not want to damage/change them after the match. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. attachment: Capture.JPG___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
One side-effect is that you run into possibilities of oscillation. This have happend and was the cause of a GPS outage in a US Harbour a few years back. What was a wise design became an enemy due to a subtle change in part. Don't recall if the part was replaced by an equivalent or same part-number, but the new version didn't work as expected during all conditions... Yes, one of the most probable problems. I've read the story about the GPS outage in that harbour, as I remember it was caused by a failure in one TV antenna amplifier on a boat - but I don't remember if it was an isolated case due to a failure (or to a bad repair replacing the part with a similar one), or was a more 'endemic' problem :) Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I think this is pretty common with transistors. A company is making a particular part, then a new, better part comes along that exceeds the spec of an existing part. So they start putting the new die into the old package as well as making the new part. Fewer dice to make likely means cheaper and less hassels. And they don't tell anyone. Win-win, except the new part has a much higher Ft for example and formerly stable circuits now oscillate badly. Tilt! -John = Hello, [snip] Another story is about 2N3771 transistor, initially a single-diffussed part, but later an epitaxial base part - with a lot more gain bandwidth product. But since the 'new' 2N3771 meets and exceeds original 2N3771 specs, the same part number was used - but the part is quite different (and published specs continues being the JEDEC ones). So you can imagine that in some applications it would be quite a lot of difference if you breadboard with the older, and during the manufacturing phase you (probably without knowing it) switch to the new part. [snip] Best regards, Javier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I think it was a one-off failure: http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776 -John === One side-effect is that you run into possibilities of oscillation. This have happend and was the cause of a GPS outage in a US Harbour a few years back. What was a wise design became an enemy due to a subtle change in part. Don't recall if the part was replaced by an equivalent or same part-number, but the new version didn't work as expected during all conditions... Yes, one of the most probable problems. I've read the story about the GPS outage in that harbour, as I remember it was caused by a failure in one TV antenna amplifier on a boat - but I don't remember if it was an isolated case due to a failure (or to a bad repair replacing the part with a similar one), or was a more 'endemic' problem :) Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. Or, as Javier said: I periodically receive PCNs (product change notifications) from EBV Elektronik, which is a quite big european semiconductor distributor, So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 08/14/2010 07:10 PM, J. Forster wrote: I think it was a one-off failure: http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776 This is the incident I described, but notice that there where three sources, two of which was different antennas with the same amplifier... both instances had the problem. I have seen another report from this incident where they pointed out the differences in component for the same design. A very benign subtle difference... Doesn't seem to find it right now. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
El 14/08/2010 19:17, Hal Murray escribió: So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. Yes. I'm not a high volume customer, only mid-to-low :) But I receive the PCNs even for components that I've only purchased one 50pcs bar for a special project. But I'm not sure if all manufacturers are the same. This example from NXP is very very detailed, in other cases there is only a note that production has changed from one factory to another. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi Not so much. Mil grade just makes sure they qualify a change. At the time we had the issues the volume on the transistors was quite high. The cost os screening was still prohibitive. They write the specs with very few limits for a reason Bob On Aug 14, 2010, at 1:17 PM, Hal Murray hmur...@megapathdsl.net wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. Or, as Javier said: I periodically receive PCNs (product change notifications) from EBV Elektronik, which is a quite big european semiconductor distributor, So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi I seem to get weekly notices about a resin changing or a new date code format. Silicon changes don't seem to be on the same system. That's still better than it was 30 years back. Bob On Aug 14, 2010, at 1:38 PM, Javier Herrero jherr...@hvsistemas.es wrote: El 14/08/2010 19:17, Hal Murray escribió: So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. Yes. I'm not a high volume customer, only mid-to-low :) But I receive the PCNs even for components that I've only purchased one 50pcs bar for a special project. But I'm not sure if all manufacturers are the same. This example from NXP is very very detailed, in other cases there is only a note that production has changed from one factory to another. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I sometimes get some PCNs about process changes on silicon (new process or new masks). I suppose that depends on manufacturers :) Regards, Javier El 14/08/2010 19:49, Bob Camp escribió: Hi I seem to get weekly notices about a resin changing or a new date code format. Silicon changes don't seem to be on the same system. That's still better than it was 30 years back. Bob On Aug 14, 2010, at 1:38 PM, Javier Herrerojherr...@hvsistemas.es wrote: El 14/08/2010 19:17, Hal Murray escribió: So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. Yes. I'm not a high volume customer, only mid-to-low :) But I receive the PCNs even for components that I've only purchased one 50pcs bar for a special project. But I'm not sure if all manufacturers are the same. This example from NXP is very very detailed, in other cases there is only a note that production has changed from one factory to another. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17 FAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Mil specs cover a number of things that are not always in the commercial specs, but not always, and mil spec parts are going the way of the dodo. Nobody wants to make them, except the local garage shop which does not mind selling you $0.02 parts for $60 (quite common) and the worst is that these parts are often made in very small runs from the old masks, or they are custom packaged dies bought from commercial sources and screened to meet the requirements and end up having very poor reliability because the small runs do not allow the quality of commercial parts made in the gazillion. Quite a paradox!!! In my 30 years experience designing military and space hardware, I now believe the commercial grade plastic parts you get from Digikey are quite a bit better than the expensive mil spec ones in the hermetic packages, even when rated 0-70C and when used in a humid environment. Of course, if you have to have hermetic parts to satisfy an explicit customer requirement, that's another story, even though I have been fairly successful at obtaining waivers from customers in that regard. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Hal Murray hmur...@megapathdsl.net Sender: time-nuts-boun...@febo.com Date: Sat, 14 Aug 2010 10:17:32 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Simulation Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. Or, as Javier said: I periodically receive PCNs (product change notifications) from EBV Elektronik, which is a quite big european semiconductor distributor, So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] lost posts
My last two posts made it to the Archives at febo.com and I guess other members mail boxes, but not my in box or spam folder. Just wonder why as this doesn't seem to happen with time-nuts posts by others ? Is this a yahoo mail problem ? Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
When I was building spacecraft payloads for the USAF, there was a lot of resistance to using commercial parts. If something failed, you had to right back to square one with the acceptance tests, and that took months. Often we just used stuff from the Apollo QPL. -John = Mil specs cover a number of things that are not always in the commercial specs, but not always, and mil spec parts are going the way of the dodo. Nobody wants to make them, except the local garage shop which does not mind selling you $0.02 parts for $60 (quite common) and the worst is that these parts are often made in very small runs from the old masks, or they are custom packaged dies bought from commercial sources and screened to meet the requirements and end up having very poor reliability because the small runs do not allow the quality of commercial parts made in the gazillion. Quite a paradox!!! In my 30 years experience designing military and space hardware, I now believe the commercial grade plastic parts you get from Digikey are quite a bit better than the expensive mil spec ones in the hermetic packages, even when rated 0-70C and when used in a humid environment. Of course, if you have to have hermetic parts to satisfy an explicit customer requirement, that's another story, even though I have been fairly successful at obtaining waivers from customers in that regard. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Hal Murray hmur...@megapathdsl.net Sender: time-nuts-boun...@febo.com Date: Sat, 14 Aug 2010 10:17:32 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Simulation Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. Or, as Javier said: I periodically receive PCNs (product change notifications) from EBV Elektronik, which is a quite big european semiconductor distributor, So maybe it doesn't take a high volume, you just have to get plugged into the right paperwork flow and then read all the fine print to see if the change is interesting. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS SVN26 / PRN26
It's being tracked ok by our FireFly-1A right now, see here: http://www.jackson-labs.com/images/gpsstat.htm Bye, Said Sent From iPhone On Aug 13, 2010, at 14:46, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 08/13/2010 09:41 PM, Henry Hallam wrote: Is anyone else having issues with satellite 26 at the moment? There is scheduled activity for it: GPS OPERATIONAL ADVISORY225 SUBJ: GPS STATUS 13 AUG 2010 1. SATELLITES, PLANES, AND CLOCKS (CS=CESIUM RB=RUBIDIUM): A. BLOCK I : NONE B. BLOCK II: PRNS 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 PLANE : SLOT B11, D1, C2, D4, E3, C5, A4, A3, A1, E6, D2, B4, F3, F1 CLOCK : RB, RB, CS, RB, RB, RB, RB, CS, CS, CS, RB, RB, RB, RB BLOCK II: PRNS 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 PLANE : SLOT F2, B1, C4, E4, C3, E1, D3, E2, F4, D21, B2, F21, A6, B3 CLOCK : RB, RB, RB, RB, RB, RB, RB, RB, RB, CS, RB, RB, CS, RB BLOCK II: PRNS 29, 30, 31, 32 PLANE : SLOT C1, B21, A2, E5 CLOCK : RB, CS, RB, RB 2. CURRENT ADVISORIES AND FORECASTS : A. FORECASTS: FOR SEVEN DAYS AFTER EVENT CONCLUDES. NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 2010102 222106Z JUL 201016 FCSTDV 210/1345-211/0145 2010103 292144Z JUL 201016 FCSTSUMM 210/1411-210/2126 2010104 292146Z JUL 201026 FCSTDV 215/1715-216/1715 2010105 03Z AUG 201026 FCSTSUMM 215/1726-215/ B. ADVISORIES: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) C. GENERAL: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 2009025 061455Z APR 2009 GENERAL /-/ 2010068 111551Z APR 2010 GENERAL /-/ Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 8/14/2010 10:08 AM, J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John This is, easily said, a wonderful goal, and absolute fantasy. It's optimistic at best to expect someone to anticipate all contingencies. It's certainly good practice to specific critical parameters, but it's rarely makes economic sense to specify every possible detail. As to relying upon unspecified parameters, most datasheets are woefully incomplete. If you are going to use any significant number parts, it's unlikely that you'll be able to get everything specified, much less get compliance commitments for each parameter. Few vendors are willing to do the testing required to guarantee a substantial number of parameters, and the simple reason is no one is willing to pay for it. I've spent quite a bit of time dealing with maintenance of military systems that would be long obsolete in any other business. After obsolescence, the number one problem was parts that meet all published specs, but had changed performance so much (for better or worse) that they no longer functioned in the application. A common problem is Ft or gain, but leakages are often orders of magnitude different. As often as not, they were much worse. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS SVN26 / PRN26
Right, but that was over days ago. I think my problem was just some unusually strong multipath. Thanks H On Aug 13, 2010 2:46 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 08/13/2010 09:41 PM, Henry Hallam wrote: Is anyone else having issues with satellite 26 at the moment? There is scheduled activity for it: GPS OPERATIONAL ADVISORY 225 SUBJ: GPS STATUS 13 AUG 2010 1. SATELLITES, PLANES, AND CLOCKS (CS=CESIUM RB=RUBIDIUM): A. BLOCK I : NONE B. BLOCK II: PRNS 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 PLANE : SLOT B11, D1, C2, D4, E3, C5, A4, A3, A1, E6, D2, B4, F3, F1 CLOCK : RB, RB, CS, RB, RB, RB, RB, CS, CS, CS, RB, RB, RB, RB BLOCK II: PRNS 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 PLANE : SLOT F2, B1, C4, E4, C3, E1, D3, E2, F4, D21, B2, F21, A6, B3 CLOCK : RB, RB, RB, RB, RB, RB, RB, RB, RB, CS, RB, RB, CS, RB BLOCK II: PRNS 29, 30, 31, 32 PLANE : SLOT C1, B21, A2, E5 CLOCK : RB, CS, RB, RB 2. CURRENT ADVISORIES AND FORECASTS : A. FORECASTS: FOR SEVEN DAYS AFTER EVENT CONCLUDES. NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 2010102 222106Z JUL 2010 16 FCSTDV 210/1345-211/0145 2010103 292144Z JUL 2010 16 FCSTSUMM 210/1411-210/2126 2010104 292146Z JUL 2010 26 FCSTDV 215/1715-216/1715 2010105 03Z AUG 2010 26 FCSTSUMM 215/1726-215/ B. ADVISORIES: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) C. GENERAL: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 2009025 061455Z APR 2009 GENERAL /-/ 2010068 111551Z APR 2010 GENERAL /-/ Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 8/14/2010 12:10 PM, J. Forster wrote: I think it was a one-off failure: http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776 -John I wish it were a one off. I and friends at cell ops chase these things all of the time in the cellular and public safety bands. This one just happened to be in a location that covered a wide area in a densely populated area. -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I can't recall hearing of other wide-area jamming of GPS, but they may not have reached the media. Certainly, that incident alone demonstrates the vulnerability of GPS and argues against the shutdown of LORAN. -Jo0hn === On 8/14/2010 12:10 PM, J. Forster wrote: I think it was a one-off failure: http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776 -John I wish it were a one off. I and friends at cell ops chase these things all of the time in the cellular and public safety bands. This one just happened to be in a location that covered a wide area in a densely populated area. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On 8/14/2010 10:08 AM, J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John This is, easily said, a wonderful goal, and absolute fantasy. It's optimistic at best to expect someone to anticipate all contingencies. It's certainly good practice to specific critical parameters, but it's rarely makes economic sense to specify every possible detail. OK, important uncontrolled parameters. For example, I'd consider things like hFE; VCEsat; VCBO, fT and others important, but not the package capacitance in a low frequency transistor. There are clearly unimportant parameters and essentially irrelevant ones. That's where experience and good judgement comes in. If your circuit is not stable with a high fT part, that needs to be tested or the design fixed. As to relying upon unspecified parameters, most datasheets are woefully incomplete. If you are going to use any significant number parts, it's unlikely that you'll be able to get everything specified, much less get compliance commitments for each parameter. Few vendors are willing to do the testing required to guarantee a substantial number of parameters, and the simple reason is no one is willing to pay for it. If your design is that critical, you may have to do incoming inspectrion/selection or send the parts to a company that does. I've spent quite a bit of time dealing with maintenance of military systems that would be long obsolete in any other business. After obsolescence, the number one problem was parts that meet all published specs, but had changed performance so much (for better or worse) that they no longer functioned in the application. A common problem is Ft or gain, but leakages are often orders of magnitude different. As often as not, they were much worse. Certainly, old Ge power transistors have ICBO issues. -John === -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi It's a very rare thing to see jelly bean parts screened for RF parameters. Much more common to catch and fix an issue at the board level. Pretty rare to see discrete RF anymore anyway. Bob On Aug 14, 2010, at 3:56 PM, J. Forster j...@quik.com wrote: On 8/14/2010 10:08 AM, J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John This is, easily said, a wonderful goal, and absolute fantasy. It's optimistic at best to expect someone to anticipate all contingencies. It's certainly good practice to specific critical parameters, but it's rarely makes economic sense to specify every possible detail. OK, important uncontrolled parameters. For example, I'd consider things like hFE; VCEsat; VCBO, fT and others important, but not the package capacitance in a low frequency transistor. There are clearly unimportant parameters and essentially irrelevant ones. That's where experience and good judgement comes in. If your circuit is not stable with a high fT part, that needs to be tested or the design fixed. As to relying upon unspecified parameters, most datasheets are woefully incomplete. If you are going to use any significant number parts, it's unlikely that you'll be able to get everything specified, much less get compliance commitments for each parameter. Few vendors are willing to do the testing required to guarantee a substantial number of parameters, and the simple reason is no one is willing to pay for it. If your design is that critical, you may have to do incoming inspectrion/selection or send the parts to a company that does. I've spent quite a bit of time dealing with maintenance of military systems that would be long obsolete in any other business. After obsolescence, the number one problem was parts that meet all published specs, but had changed performance so much (for better or worse) that they no longer functioned in the application. A common problem is Ft or gain, but leakages are often orders of magnitude different. As often as not, they were much worse. Certainly, old Ge power transistors have ICBO issues. -John === -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I've seen audio range power amps that will oscillate on a part of a cycle because an output device with a higher fT was installed. Older vintage parts with the same type JEDEC number never did that. -John Hi It's a very rare thing to see jelly bean parts screened for RF parameters. Much more common to catch and fix an issue at the board level. Pretty rare to see discrete RF anymore anyway. Bob On Aug 14, 2010, at 3:56 PM, J. Forster j...@quik.com wrote: On 8/14/2010 10:08 AM, J. Forster wrote: FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or instructions in a production design is a fool. If you are that silly, you must fully specify the selection criteria. -John This is, easily said, a wonderful goal, and absolute fantasy. It's optimistic at best to expect someone to anticipate all contingencies. It's certainly good practice to specific critical parameters, but it's rarely makes economic sense to specify every possible detail. OK, important uncontrolled parameters. For example, I'd consider things like hFE; VCEsat; VCBO, fT and others important, but not the package capacitance in a low frequency transistor. There are clearly unimportant parameters and essentially irrelevant ones. That's where experience and good judgement comes in. If your circuit is not stable with a high fT part, that needs to be tested or the design fixed. As to relying upon unspecified parameters, most datasheets are woefully incomplete. If you are going to use any significant number parts, it's unlikely that you'll be able to get everything specified, much less get compliance commitments for each parameter. Few vendors are willing to do the testing required to guarantee a substantial number of parameters, and the simple reason is no one is willing to pay for it. If your design is that critical, you may have to do incoming inspectrion/selection or send the parts to a company that does. I've spent quite a bit of time dealing with maintenance of military systems that would be long obsolete in any other business. After obsolescence, the number one problem was parts that meet all published specs, but had changed performance so much (for better or worse) that they no longer functioned in the application. A common problem is Ft or gain, but leakages are often orders of magnitude different. As often as not, they were much worse. Certainly, old Ge power transistors have ICBO issues. -John === -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. just so.. In the space business, we call it traceability to sand... you haven't lived til someone has a failed 2n, somwhere on some piece of critical hardware, and they issue a GIDEP alert, and then the mission assurance folks call you up and ask, you don't by any chance have 2N's in your flight hardware do you?.. then there's the whole manufacturer and date code hunt.. Looking through the build documentation to find out. (or worse yet, if you had decided for some reason to use the prototype, which you didn't keep such good records on, but which you have photos of, and trying to read the date codes off the assembled item with a magnifying glass) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Regulating a pendulum clock
In my post below I didn't understand how a constant electromagnet on the side of the pendulum could adjust the pendulum rate. Well I've worked it out. Despite common misconceptions pendulum swing rate is not independent of amplitude. It is to the first order but not when calculated properly. The magnet when applied either reduces or increases the amplitude and hence makes minor adjustments in timing. Pretty neat for 40s technology. Jim Palfreyman On Sunday, August 8, 2010, Jim Palfreyman jim77...@gmail.com wrote: Hi all, I have a Seimens master clock with a Reiffler pendulum. A lovely piece of work that used to provide time services in the 40s. Being a master clock it has contacts that open and close on each pendulum swing and so I can monitor it's accuracy quite easily using gps and my 5370B. I've adjusted it as best I can and the best I can get is about 50 ms over 24 hours. However that was a one off. Temp and air pressure cause variations of up to 300 ms and it changes direction too. Basically it's hard to keep accurate. It also has a coil mounted near the pendulum and a fixed magnet on the pendulum bar and this coil connects to a box down below with a meter and a knob. They are labelled in sec/day. The electronics in the box are not clear (being quite old) but by measuring the current in the coil it quite simply increases the current one way to slow the clock and the other way to speed it up. (I'll admit the physics of this doesn't make sense to me - but it works!) It's about 25v in the coil and goes up to 60mA max. Even at levels of 2mA has an effect. Using this control it's quite easy to manually bring the clock back to the right time if it's say half a second fast. What I want to do is control the current in the coil with a micro controller which I have attached to a rubidium oscillator. Getting the pps from the pendulum clock in and comparing to actual time is easy, but I need a way to control the current through the coil so it can dynamically adjust the clock. I need the current to go from say -10 to +10 mA (at 25v) and this needs to be controlled via a micro controller output (which goes from 0 to 5 with 2.5 being the 0mA point). I can either use the D/A in the controller (or PWM an output I suppose). I'd appreciate some thoughts on circuits to do this. Software side is not a problem. Jim Palfreyman ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
On Apollo they had file cabinets full of drawers for IBM punch cards, except each had a microfilm insert. They could trace a single #6-32 screw back to the mine the iron ore came from. -John = Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. just so.. In the space business, we call it traceability to sand... you haven't lived til someone has a failed 2n, somwhere on some piece of critical hardware, and they issue a GIDEP alert, and then the mission assurance folks call you up and ask, you don't by any chance have 2N's in your flight hardware do you?.. then there's the whole manufacturer and date code hunt.. Looking through the build documentation to find out. (or worse yet, if you had decided for some reason to use the prototype, which you didn't keep such good records on, but which you have photos of, and trying to read the date codes off the assembled item with a magnifying glass) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Once I had a batch of JANTX 2NA (with all the paperwork) that were PNPs. They actually were marked JANTX 2NA. This was for a mil job in the 80's. We did not fool around with the mil specs back then. I was a young engineer then and not all that involved in the process, so I was kept somewhat out of the process that followed. I wish I has seen QA and purchasing explain that one :) Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: jimlux jim...@earthlink.net Sender: time-nuts-boun...@febo.com Date: Sat, 14 Aug 2010 14:42:39 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Simulation Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. just so.. In the space business, we call it traceability to sand... you haven't lived til someone has a failed 2n, somwhere on some piece of critical hardware, and they issue a GIDEP alert, and then the mission assurance folks call you up and ask, you don't by any chance have 2N's in your flight hardware do you?.. then there's the whole manufacturer and date code hunt.. Looking through the build documentation to find out. (or worse yet, if you had decided for some reason to use the prototype, which you didn't keep such good records on, but which you have photos of, and trying to read the date codes off the assembled item with a magnifying glass) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] PicTic Data
Attached is my first pictic ii data. It is the difference between the PPS output of a Trak 8820 and a Odetics Comsync. Turned on the counter display at the end of the run to show that most of the data was the interpolars. Stanley 001073 001075 001072 001072 001066 001068 001066 001068 001063 001068 001065 001066 001067 001067 001071 001075 001074 001072 001075 001079 001078 001081 001080 001084 001087 001089 001090 001092 001090 001094 001096 001098 001099 001102 001106 001105 001112 001112 00 001117 001118 001118 001123 001128 001127 001130 001129 001121 001124 001118 001116 001114 001112 001108 001103 001102 001098 001096 001092 001090 001085 001084 001082 001078 001074 001073 001074 001074 001074 001071 001069 001066 001068 001068 001069 001062 001066 001065 001065 001065 001065 001061 001062 001065 001064 001062 001062 001063 001060 001059 001061 001062 001061 001058 001058 001059 001059 001059 001059 001057 001056 001056 001058 001057 001056 001056 001057 001055 001058 001058 001058 001059 001057 001057 001055 001058 001057 001057 001060 001064 001064 001067 001070 001067 001072 001073 001077 001079 001079 001081 001084 001089 001091 001092 001092 001093 001096 001098 001099 001100 001103 001099 001097 001094 001092 001091 001090 001087 001088 001089 001088 001089 001087 001086 001086 001082 001080 001082 001080 001081 001082 001084 001084 001089 001092 001091 001095 001096 001097 001102 001103 001103 001107 001106 001113 001112 001116 001119 001121 001124 001122 001125 001128 001130 001132 001135 001138 001139 001141 001145 001147 001148 001143 001137 001137 001134 001131 001131 001127 001124 001120 001118 00 001108 001109 001103 001102 001097 001096 001087 001087 001084 001082 001078 001079 001072 001071 001065 001062 001057 001053 001048 001046 001043 001041 001038 001035 001032 001032 001031 001031 001028 001029 001028 001028 001028 001024 001026 001024 001023 001025 001022 001022 001020 001021 001022 001019 001019 001022 001020 001020 001020 001021 001019 001022 001021 001017 001021 001019 001021 001018 001020 001018 001018 001016 001019 001020 001017 001016 001018 001015 001017 001017 001015 001016 001013 001017 001011 001015 001012 001011 001013 001008 001012 001010 001009 001014 001008 001008 001007 001007 001006 001007 001006 001003 001005 001003 001006 001003 001003 001002 001004 001000 000999 000997 000999 000998 000994 000993 000995 000998 000993 000991 000994 000993 000991 000988 000988 000992 000990 000985 000988 000990 000988 000988 000988 000987 000986 000986 000988 000986 000984 000983 000982 000983 000983 000982 000978 000980 000982 000979 000977 000978 000977 000976 000974 000975 000976 000974 000972 000970 000972 000973 000974 000974 000975 000971 000973 000974 000973 000974 000974 000972 000971 000972 000972 000971 000974 000971 000969 000968 000966 000966 000966 000968 000969 000965 000962 000964 000961 000964 000962 000958 000957 000960 000959 000957 000958 000957 000957 000957 000953 000950 000949 000950 000949
Re: [time-nuts] Simulation
Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Didier Juges Sent: Saturday, August 14, 2010 6:18 PM To: Time-Nuts Subject: Re: [time-nuts] Simulation Once I had a batch of JANTX 2NA (with all the paperwork) that were PNPs. They actually were marked JANTX 2NA. This was for a mil job in the 80's. We did not fool around with the mil specs back then. I was a young engineer then and not all that involved in the process, so I was kept somewhat out of the process that followed. I wish I has seen QA and purchasing explain that one :) Didier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Surely all this is a case of an engineer being able to read..specifications :-)) Manufactures specify to sell parts, most of the important parameter are minimum values, and the range is as wide as it can be. If you want a parameter bracketed then you must specify that when buying and pay the premium or take the expense of testing incomming batches for sensitive parameters. I used to give lectures to new engineers on reading specifications .and what Absolute maximum actually means. Clever engineers also love using operations that rely on unspecified parameters. For example using a stock switching diode as a spike quencher in a relay driver. The usually work (but not always!) but are generally not specified for that service. Spice parameters are probably a few typical samples of even the one I happened to choose to measure!! I had a case of some +/-12v transistor logic which made it was into a big telecoms project. the prototypes worked fine. By the time of bulk manufacture the supplier of the the main transistor had had several cost improvement stages. The result was the kit was unreliable. The problem was that first the base junction were swung to -12v by the 0 logic state and second from a transistor with a fairly simple round dot geometry emitter, the device had been replaced by an interdigital high ft chip (it still met the basic greater than specs.) The interdigital device suffered severe loss of gain after a period of avalanching at several millamps (I think it also suffered electromigration) much more than the circular geometry transistors. I think this was due to the increased emitter periphery length. It was solved by placing a simple diode in the emitter leg, or a clamp on the base. The engineer had not read, or not understood the meaning of the Vebmax = 5v parameter, and his prototype had worked. The production side were not very happy but eventually were forced to junk thousands of 8inch square pcbs and do a re-layout. This was in the days before computer simulation !! It might have helped! Alan G3NYK - Original Message - From: jimlux jim...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, August 14, 2010 10:42 PM Subject: Re: [time-nuts] Simulation Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. just so.. In the space business, we call it traceability to sand... you haven't lived til someone has a failed 2n, somwhere on some piece of critical hardware, and they issue a GIDEP alert, and then the mission assurance folks call you up and ask, you don't by any chance have 2N's in your flight hardware do you?.. then there's the whole manufacturer and date code hunt.. Looking through the build documentation to find out. (or worse yet, if you had decided for some reason to use the prototype, which you didn't keep such good records on, but which you have photos of, and trying to read the date codes off the assembled item with a magnifying glass) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Alternative time interval interpolation technique
A method that measures the phase of a damped LC circuit oscillatory transient triggered by the event to be timestamped: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20time%20resolution%20time-to-digital%20converter%20employing%20passive%20resonating%20circuits.pdf A dual of the circuit is readily devised using a CMOS gate plus an open drain (or equivalent) gate output for damping/quenching. However the ADC employed needs to be able to capture a sample burst at a relatively high sample rate. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Alternative time interval interpolation technique
http://risorse.dei.polimi.it/digital/pubblications.html then scroll down Stanley - Original Message From: Bruce Griffiths bruce.griffi...@xtra.co.nz To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 7:05:03 PM Subject: [time-nuts] Alternative time interval interpolation technique A method that measures the phase of a damped LC circuit oscillatory transient triggered by the event to be timestamped: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20time%20resolution%20time-to-digital%20converter%20employing%20passive%20resonating%20circuits.pdf A dual of the circuit is readily devised using a CMOS gate plus an open drain (or equivalent) gate output for damping/quenching. However the ADC employed needs to be able to capture a sample burst at a relatively high sample rate. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi Simulation might or might not have helped. 1) Was Vbe breakdown even included in the Spice model 2) If so did it ring bells (rare) or did it just clip without error ( common ) 3) Would the same designer who didn't understand it in the first place have seen it clipping at -5 and concluded looks to be in spec at -5 4) Would any of it be reviewed in light of the new transistor or was the guy on another project by then My favorite in the absolute max Vbe category is the typical class C RF amp. Look at the spec, check a few thousand working boards. Scratch head and move on. Lots of reverse bias on the base and they run forever. Bob On Aug 14, 2010, at 7:47 PM, Alan Melia alan.me...@btinternet.com wrote: Surely all this is a case of an engineer being able to read..specifications :-)) Manufactures specify to sell parts, most of the important parameter are minimum values, and the range is as wide as it can be. If you want a parameter bracketed then you must specify that when buying and pay the premium or take the expense of testing incomming batches for sensitive parameters. I used to give lectures to new engineers on reading specifications .and what Absolute maximum actually means. Clever engineers also love using operations that rely on unspecified parameters. For example using a stock switching diode as a spike quencher in a relay driver. The usually work (but not always!) but are generally not specified for that service. Spice parameters are probably a few typical samples of even the one I happened to choose to measure!! I had a case of some +/-12v transistor logic which made it was into a big telecoms project. the prototypes worked fine. By the time of bulk manufacture the supplier of the the main transistor had had several cost improvement stages. The result was the kit was unreliable. The problem was that first the base junction were swung to -12v by the 0 logic state and second from a transistor with a fairly simple round dot geometry emitter, the device had been replaced by an interdigital high ft chip (it still met the basic greater than specs.) The interdigital device suffered severe loss of gain after a period of avalanching at several millamps (I think it also suffered electromigration) much more than the circular geometry transistors. I think this was due to the increased emitter periphery length. It was solved by placing a simple diode in the emitter leg, or a clamp on the base. The engineer had not read, or not understood the meaning of the Vebmax = 5v parameter, and his prototype had worked. The production side were not very happy but eventually were forced to junk thousands of 8inch square pcbs and do a re-layout. This was in the days before computer simulation !! It might have helped! Alan G3NYK - Original Message - From: jimlux jim...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, August 14, 2010 10:42 PM Subject: Re: [time-nuts] Simulation Hal Murray wrote: Line got moved to other side of big ocean. Process got tweaked beta is now 4x what it was. I'm pretty sure that military grade parts have paperwork and processes to cover that case. I expect it costs a lot. I think the same sort of service is available to high volume customers at a less than military price. just so.. In the space business, we call it traceability to sand... you haven't lived til someone has a failed 2n, somwhere on some piece of critical hardware, and they issue a GIDEP alert, and then the mission assurance folks call you up and ask, you don't by any chance have 2N's in your flight hardware do you?.. then there's the whole manufacturer and date code hunt.. Looking through the build documentation to find out. (or worse yet, if you had decided for some reason to use the prototype, which you didn't keep such good records on, but which you have photos of, and trying to read the date codes off the assembled item with a magnifying glass) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Alternative time interval interpolation technique
Scroll to the bottom of the first list, or search for 'LC tanks' Don't know why Bruce's link doesn't work, but I get 404 - file not found. Bill Hawkins -Original Message- From: Stanley Reynolds http://risorse.dei.polimi.it/digital/pubblications.html then scroll down Stanley - Original Message From: Bruce Griffiths bruce.griffi...@xtra.co.nz A method that measures the phase of a damped LC circuit oscillatory transient triggered by the event to be timestamped: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20 time%20resolution%20time-to-digital%20converter%20employing%20passive%20reso nating%20circuits.pdf A dual of the circuit is readily devised using a CMOS gate plus an open drain (or equivalent) gate output for damping/quenching. However the ADC employed needs to be able to capture a sample burst at a relatively high sample rate. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Yes, I guess it was. I have been in the military business since 1967, and, certainly seen my share. Besides all of the screw ups, there was one that really took the cake. I once worked for a company that had to build a radio that was strictly build-to-print. The original drawing had a mil-spec yellow band resistor of value X in the front end. Well, with that resistor the NF could not be met. They could meet it with a value Y. Pleading with the government reps made no difference. Finally, the head of the company QA department wrote a letter to AB and actually asked them to provide resistors with value Y, but, color code them with the value X. Everyone signed off on it, and, everything was fine. I still have a copy of the letter someplace. I just got back from Fort Bragg where I was involved in certifying a system at Ka band. The antenna is a 30 footer and had only a 10 degree elevation look angle to see the bird needed. Well, guess what? There are three 30 foot dishes in the system, the other two being Ku, and this antenna was between them looking right through one of the Ku antennas. Really messed with the patterns. Now, based on my input they are changing the feed assembly and all of the RF between the two antennas to prevent the blockage. It will take a month. I am sure I will be there again. A few simple examples of hundreds. - Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gandal...@aol.com Sent: Saturday, August 14, 2010 6:52 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Simulation In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT: leaching was, Alternative time interval interpolation technique
When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Stanley - Original Message From: Bill Hawkins b...@iaxs.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 7:35:53 PM Subject: Re: [time-nuts] Alternative time interval interpolation technique Scroll to the bottom of the first list, or search for 'LC tanks' Don't know why Bruce's link doesn't work, but I get 404 - file not found. Bill Hawkins -Original Message- From: Stanley Reynolds http://risorse.dei.polimi.it/digital/pubblications.html then scroll down Stanley - Original Message From: Bruce Griffiths bruce.griffi...@xtra.co.nz A method that measures the phase of a damped LC circuit oscillatory transient triggered by the event to be timestamped: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20 time%20resolution%20time-to-digital%20converter%20employing%20passive%20reso nating%20circuits.pdf A dual of the circuit is readily devised using a CMOS gate plus an open drain (or equivalent) gate output for damping/quenching. However the ADC employed needs to be able to capture a sample burst at a relatively high sample rate. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique
stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
?? The yellow banded R means established reliability. I see no reason why the NF should be any different then one w/o the yellow band. They are the same part, only one is tested more. Not white band perchance? -John === Yes, I guess it was. I have been in the military business since 1967, and, certainly seen my share. Besides all of the screw ups, there was one that really took the cake. I once worked for a company that had to build a radio that was strictly build-to-print. The original drawing had a mil-spec yellow band resistor of value X in the front end. Well, with that resistor the NF could not be met. They could meet it with a value Y. Pleading with the government reps made no difference. Finally, the head of the company QA department wrote a letter to AB and actually asked them to provide resistors with value Y, but, color code them with the value X. Everyone signed off on it, and, everything was fine. I still have a copy of the letter someplace. I just got back from Fort Bragg where I was involved in certifying a system at Ka band. The antenna is a 30 footer and had only a 10 degree elevation look angle to see the bird needed. Well, guess what? There are three 30 foot dishes in the system, the other two being Ku, and this antenna was between them looking right through one of the Ku antennas. Really messed with the patterns. Now, based on my input they are changing the feed assembly and all of the RF between the two antennas to prevent the blockage. It will take a month. I am sure I will be there again. A few simple examples of hundreds. - Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gandal...@aol.com Sent: Saturday, August 14, 2010 6:52 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Simulation In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique
oh well no credit for me, but what happened to the missing space when so many other spaces made it thru as %20 ? - Original Message From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 8:27:09 PM Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
I only mentioned the yellow band because of reliability. Seems like the original resistor was 220 ohms and the one that actually met the required NF was 330 (or the other way around). So, it was not the yellow band that had to be changed. - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Saturday, August 14, 2010 9:43 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Simulation ?? The yellow banded R means established reliability. I see no reason why the NF should be any different then one w/o the yellow band. They are the same part, only one is tested more. Not white band perchance? -John === Yes, I guess it was. I have been in the military business since 1967, and, certainly seen my share. Besides all of the screw ups, there was one that really took the cake. I once worked for a company that had to build a radio that was strictly build-to-print. The original drawing had a mil-spec yellow band resistor of value X in the front end. Well, with that resistor the NF could not be met. They could meet it with a value Y. Pleading with the government reps made no difference. Finally, the head of the company QA department wrote a letter to AB and actually asked them to provide resistors with value Y, but, color code them with the value X. Everyone signed off on it, and, everything was fine. I still have a copy of the letter someplace. I just got back from Fort Bragg where I was involved in certifying a system at Ka band. The antenna is a 30 footer and had only a 10 degree elevation look angle to see the bird needed. Well, guess what? There are three 30 foot dishes in the system, the other two being Ku, and this antenna was between them looking right through one of the Ku antennas. Really messed with the patterns. Now, based on my input they are changing the feed assembly and all of the RF between the two antennas to prevent the blockage. It will take a month. I am sure I will be there again. A few simple examples of hundreds. - Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gandal...@aol.com Sent: Saturday, August 14, 2010 6:52 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Simulation In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Hi I think it was the value that changed. Somebody typo'd 10k at 10 ohms Bob On Aug 14, 2010, at 9:42 PM, J. Forster j...@quik.com wrote: ?? The yellow banded R means established reliability. I see no reason why the NF should be any different then one w/o the yellow band. They are the same part, only one is tested more. Not white band perchance? -John === Yes, I guess it was. I have been in the military business since 1967, and, certainly seen my share. Besides all of the screw ups, there was one that really took the cake. I once worked for a company that had to build a radio that was strictly build-to-print. The original drawing had a mil-spec yellow band resistor of value X in the front end. Well, with that resistor the NF could not be met. They could meet it with a value Y. Pleading with the government reps made no difference. Finally, the head of the company QA department wrote a letter to AB and actually asked them to provide resistors with value Y, but, color code them with the value X. Everyone signed off on it, and, everything was fine. I still have a copy of the letter someplace. I just got back from Fort Bragg where I was involved in certifying a system at Ka band. The antenna is a 30 footer and had only a 10 degree elevation look angle to see the bird needed. Well, guess what? There are three 30 foot dishes in the system, the other two being Ku, and this antenna was between them looking right through one of the Ku antennas. Really messed with the patterns. Now, based on my input they are changing the feed assembly and all of the RF between the two antennas to prevent the blockage. It will take a month. I am sure I will be there again. A few simple examples of hundreds. - Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gandal...@aol.com Sent: Saturday, August 14, 2010 6:52 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Simulation In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Simulation
Somebody read the resistor code backwards then? Easy enough if you don't know what you're doing w/ Established Reliability parts. -John = I only mentioned the yellow band because of reliability. Seems like the original resistor was 220 ohms and the one that actually met the required NF was 330 (or the other way around). So, it was not the yellow band that had to be changed. - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Saturday, August 14, 2010 9:43 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Simulation ?? The yellow banded R means established reliability. I see no reason why the NF should be any different then one w/o the yellow band. They are the same part, only one is tested more. Not white band perchance? -John === Yes, I guess it was. I have been in the military business since 1967, and, certainly seen my share. Besides all of the screw ups, there was one that really took the cake. I once worked for a company that had to build a radio that was strictly build-to-print. The original drawing had a mil-spec yellow band resistor of value X in the front end. Well, with that resistor the NF could not be met. They could meet it with a value Y. Pleading with the government reps made no difference. Finally, the head of the company QA department wrote a letter to AB and actually asked them to provide resistors with value Y, but, color code them with the value X. Everyone signed off on it, and, everything was fine. I still have a copy of the letter someplace. I just got back from Fort Bragg where I was involved in certifying a system at Ka band. The antenna is a 30 footer and had only a 10 degree elevation look angle to see the bird needed. Well, guess what? There are three 30 foot dishes in the system, the other two being Ku, and this antenna was between them looking right through one of the Ku antennas. Really messed with the patterns. Now, based on my input they are changing the feed assembly and all of the RF between the two antennas to prevent the blockage. It will take a month. I am sure I will be there again. A few simple examples of hundreds. - Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gandal...@aol.com Sent: Saturday, August 14, 2010 6:52 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Simulation In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com writes: Not that it really matters for this thread, but, the 2NA was one of the most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP complement. - regards - Mike -- Wasn't that exactly the point that was being made?:-) regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Hi Is it shielded from drafts? Bob On Aug 14, 2010, at 10:12 PM, Stanley Reynolds stanley_reyno...@yahoo.com wrote: My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
One problem is the door opens don't move in the same direction, a rain storm did cool things off outside during the test but it was still warmer outside both times. I will place a box over the Pictic and rerun the test. Stanley - Original Message From: Stanley Reynolds stanley_reyno...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 9:38:37 PM Subject: Re: [time-nuts] PicTic Data No, the board is not in a case. An annotated graph attached. I think the 100 sec oscillations are a vane that moves up and down on the a/c unit as this is washed out on the two door opens. - Original Message From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 9:18:44 PM Subject: Re: [time-nuts] PicTic Data Hi Is it shielded from drafts? Bob On Aug 14, 2010, at 10:12 PM, Stanley Reynolds stanley_reyno...@yahoo.com wrote: My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique
Mea Culpa. Below is a link to the paper using SAW filters to achieve a sub ps time interval interpolator noise: http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf And the associated presentation: http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf Bruce Stanley Reynolds wrote: oh well no credit for me, but what happened to the missing space when so many other spaces made it thru as %20 ? - Original Message From: Hal Murrayhmur...@megapathdsl.net To: Discussion of precise time and frequency measurementtime-nuts@febo.com Sent: Sat, August 14, 2010 8:27:09 PM Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
A few preliminary measurements here (I'm working on getting some software support together): http://www.ke5fx.com/pictic.htm -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 7:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PicTic Data My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
John glad you are getting good results and have something to compare to. Back to me who doesn't have any knowns but lots of guessing. Attached is a run with a box cover over the pictic, run is shorter ~ 800 seconds but the box does look like it helps. I need to do a lot more testing but sometimes I just get excited :-) I imported your .txt file alongside the traces I captured. Assuming it was taken with 1 Hz on both START and STOP, it looks like the attached. You're getting the exact sort of results that I see if I feed both the START and STOP inputs at 1 Hz. My guess is that the onboard oscillator limits the performance in that case, since it has a lot of time to drift during the measurement if the two pulses occur close to 1 second apart. Even the 5370B looks much worse if driven with 1 Hz on both inputs than it does with 1 Hz at START and 10 MHz at STOP. So I think you're basically up and running OK. When I get around to trying a better clock, I'll also go back and see if the 1-pps x2 performance improves. It would be great if the next spin of the board could include sine-to-CMOS shapers for the input channels as well as an external clock input, for people who are working directly with RF signals as opposed to 1-pps. -- john, KE5FX - Original Message From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:19:46 PM Subject: Re: [time-nuts] PicTic Data A few preliminary measurements here (I'm working on getting some software support together): http://www.ke5fx.com/pictic.htm -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 7:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PicTic Data My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. attachment: capture2_freq.gifattachment: capture2_adev.gif___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Here's your first run in red, compared to your second one in green... -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 3:28 PM To: time-nuts@febo.com Subject: [time-nuts] PicTic Data Attached is my first pictic ii data. It is the difference between the PPS output of a Trak 8820 and a Odetics Comsync. Turned on the counter display at the end of the run to show that most of the data was the interpolars. Stanley attachment: compare.gif___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Thanks for looking at my data that was what I was fishing for all along :-) I was looking at the article: A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley Richard posted And thinking it would be nice to do the DSS and Mixer boards to go with the pictic II. Or changing the Pictic II to use the Acam TDC GP2 Time to Digital Converter; 2 channel w/65 ps resolution now under $30. as Bruce suggested a while back. My wants sure exceed my cans ;-) Stanley - Original Message From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 11:25:44 PM Subject: Re: [time-nuts] PicTic Data John glad you are getting good results and have something to compare to. Back to me who doesn't have any knowns but lots of guessing. Attached is a run with a box cover over the pictic, run is shorter ~ 800 seconds but the box does look like it helps. I need to do a lot more testing but sometimes I just get excited :-) I imported your .txt file alongside the traces I captured. Assuming it was taken with 1 Hz on both START and STOP, it looks like the attached. You're getting the exact sort of results that I see if I feed both the START and STOP inputs at 1 Hz. My guess is that the onboard oscillator limits the performance in that case, since it has a lot of time to drift during the measurement if the two pulses occur close to 1 second apart. Even the 5370B looks much worse if driven with 1 Hz on both inputs than it does with 1 Hz at START and 10 MHz at STOP. So I think you're basically up and running OK. When I get around to trying a better clock, I'll also go back and see if the 1-pps x2 performance improves. It would be great if the next spin of the board could include sine-to-CMOS shapers for the input channels as well as an external clock input, for people who are working directly with RF signals as opposed to 1-pps. -- john, KE5FX - Original Message From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:19:46 PM Subject: Re: [time-nuts] PicTic Data A few preliminary measurements here (I'm working on getting some software support together): http://www.ke5fx.com/pictic.htm -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 7:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PicTic Data My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Yes don't think the box did do much. I do have two different dividers here I just need too finish the projects I have. Thanks again, Stanley - Original Message From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 11:46:49 PM Subject: Re: [time-nuts] PicTic Data Here's your first run in red, compared to your second one in green... -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 3:28 PM To: time-nuts@febo.com Subject: [time-nuts] PicTic Data Attached is my first pictic ii data. It is the difference between the PPS output of a Trak 8820 and a Odetics Comsync. Turned on the counter display at the end of the run to show that most of the data was the interpolars. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Thanks for looking at my data that was what I was fishing for all along :-) You can import it the same way, actually -- install the TimeLab beta at www.ke5fx.com/timelab/setup.exe and use File-Import ASCII Phase Data to read your file. Set Nominal Frequency to 1, Numeric Field # to whichever field contains your time data (2 for capture.txt), and the 'x' field to 250E-12 to convert to seconds. That should give you the same graph I posted. Ulrich Bangert's Plotter application is also good for this sort of thing, although I don't immediately see how to make it scale the data by 250E-12 to convert it to seconds. I was looking at the article: A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley Richard posted And thinking it would be nice to do the DSS and Mixer boards to go with the pictic II. Or changing the Pictic II to use the Acam TDC GP2 Time to Digital Converter; 2 channel w/65 ps resolution now under $30. as Bruce suggested a while back. My wants sure exceed my cans ;-) Once lower measurement floors are desired and the system grows in complexity and cost, other approaches besides TICs start to look more appealing. For what it does, though, this is a really nice little board. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
An ACAM GP2 evaluation board is available here: http://shop.omegacs.net/ However an ACAM GP1 would probably be a better fit in a DMTD with a beat frequency of 10Hz or more as the GP1 has a measurement range of 200ms. Bruce Stanley Reynolds wrote: Thanks for looking at my data that was what I was fishing for all along :-) I was looking at the article: A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley Richard posted And thinking it would be nice to do the DSS and Mixer boards to go with the pictic II. Or changing the Pictic II to use the Acam TDC GP2 Time to Digital Converter; 2 channel w/65 ps resolution now under $30. as Bruce suggested a while back. My wants sure exceed my cans ;-) Stanley - Original Message From: John Milesjmi...@pop.net To: Discussion of precise time and frequency measurementtime-nuts@febo.com Sent: Sat, August 14, 2010 11:25:44 PM Subject: Re: [time-nuts] PicTic Data John glad you are getting good results and have something to compare to. Back to me who doesn't have any knowns but lots of guessing. Attached is a run with a box cover over the pictic, run is shorter ~ 800 seconds but the box does look like it helps. I need to do a lot more testing but sometimes I just get excited :-) I imported your .txt file alongside the traces I captured. Assuming it was taken with 1 Hz on both START and STOP, it looks like the attached. You're getting the exact sort of results that I see if I feed both the START and STOP inputs at 1 Hz. My guess is that the onboard oscillator limits the performance in that case, since it has a lot of time to drift during the measurement if the two pulses occur close to 1 second apart. Even the 5370B looks much worse if driven with 1 Hz on both inputs than it does with 1 Hz at START and 10 MHz at STOP. So I think you're basically up and running OK. When I get around to trying a better clock, I'll also go back and see if the 1-pps x2 performance improves. It would be great if the next spin of the board could include sine-to-CMOS shapers for the input channels as well as an external clock input, for people who are working directly with RF signals as opposed to 1-pps. -- john, KE5FX - Original Message From: John Milesjmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:19:46 PM Subject: Re: [time-nuts] PicTic Data A few preliminary measurements here (I'm working on getting some software support together): http://www.ke5fx.com/pictic.htm -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 7:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PicTic Data My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] PicTic Data
Bruce Griffiths wrote: An ACAM GP2 evaluation board is available here: http://shop.omegacs.net/ Ignore this link as I omitted to read the fine print However an ACAM GP1 would probably be a better fit in a DMTD with a beat frequency of 10Hz or more as the GP1 has a measurement range of 200ms. Bruce Stanley Reynolds wrote: Thanks for looking at my data that was what I was fishing for all along :-) I was looking at the article: A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley Richard posted And thinking it would be nice to do the DSS and Mixer boards to go with the pictic II. Or changing the Pictic II to use the Acam TDC GP2 Time to Digital Converter; 2 channel w/65 ps resolution now under $30. as Bruce suggested a while back. My wants sure exceed my cans ;-) Stanley - Original Message From: John Milesjmi...@pop.net To: Discussion of precise time and frequency measurementtime-nuts@febo.com Sent: Sat, August 14, 2010 11:25:44 PM Subject: Re: [time-nuts] PicTic Data John glad you are getting good results and have something to compare to. Back to me who doesn't have any knowns but lots of guessing. Attached is a run with a box cover over the pictic, run is shorter ~ 800 seconds but the box does look like it helps. I need to do a lot more testing but sometimes I just get excited :-) I imported your .txt file alongside the traces I captured. Assuming it was taken with 1 Hz on both START and STOP, it looks like the attached. You're getting the exact sort of results that I see if I feed both the START and STOP inputs at 1 Hz. My guess is that the onboard oscillator limits the performance in that case, since it has a lot of time to drift during the measurement if the two pulses occur close to 1 second apart. Even the 5370B looks much worse if driven with 1 Hz on both inputs than it does with 1 Hz at START and 10 MHz at STOP. So I think you're basically up and running OK. When I get around to trying a better clock, I'll also go back and see if the 1-pps x2 performance improves. It would be great if the next spin of the board could include sine-to-CMOS shapers for the input channels as well as an external clock input, for people who are working directly with RF signals as opposed to 1-pps. -- john, KE5FX - Original Message From: John Milesjmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 10:19:46 PM Subject: Re: [time-nuts] PicTic Data A few preliminary measurements here (I'm working on getting some software support together): http://www.ke5fx.com/pictic.htm -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Stanley Reynolds Sent: Saturday, August 14, 2010 7:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PicTic Data My guess as to what the data may indicate is performance of the 10 Mhz 20PPM PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems to show me leaving the room and returning via the outside door. Not sure what the ~100 sec oscillations are, need to check a/c cycle time. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
