[time-nuts] 53230A TIC and TimeLab
I have recently acquited a 53230A counter and have tried to measure ADEV of a GPSDO with it. I am suspicious of the ADEV numbers reported by TimeLab V1.31 because 1) Timelab disagrees significantly with the ADEV numbers reported by the 53230A itself. In this case, with 1 sec sample intervals, the 53230A reports an ADEV of about 370 micro Hz (or 3.7e-11). Time lab reports 1.5e-11 @0.01 sec sample period, 2e-11 @0.1 sec sample period, 6e-11 @1sec sample period - all at tau=1sec. 2) When I use TimeLab to select different sample intervals, the whole ADEV curve shifts left (with smaller sample intervals) or right (with larger sample intervals). Its as if TimeLab does not correctly account for the sample interval, but am I just not using the Timelab/counter setup correctly? Thanks! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Oscillators
Hi Bob, I'll be on vacation for the next two weeks and out of internet range part of the time. Please consider my earlier request at the appropriate time. Best regards, Dave Smith -Original Message- From: time-nuts On Behalf Of Bob Martin Sent: Wednesday, October 3, 2018 1:48 PM To: Time Nuta Subject: [time-nuts] Oscillators Time-Nuts, I'm already getting requests from people who can't read! Please don't contact me until everyone has a chance to process the list of oscillators. Cheers Bob ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7C%7C2b8c48de1be243a75f1c08d62971b4aa%7C84df9e7fe9f640afb435%7C1%7C0%7C636741965662369715sdata=GxI5qOYqKWNtl8UMIvIIka2DToZKyJT6YEjXjTQb6Eg%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NIST Time and Frequency Publication Database
Fellow time-nuts, I just wanted to remind you about the wonderful resource that the NIST Time and Frequency Publication Database is. It's a good way to find lots of good articles. https://tf.nist.gov/general/publications.htm Once you find an article, search on the writes names to find more good stuff. Today was the day when I accidentally found an article that I co-wrote. Somewhat proud of that. Interesting writers to search for is Allan, Weiss, Barnes, Howe, Walls, Nelson, Hati, Gray and Stein should get you started. "regenerative" is a good search there for regenerative dividers for instance. David Howe has written "Interpreting Oscillatory Frequency Stability Plots" for instance, which may be of some interest for some here: https://tf.nist.gov/general/pdf/1808.pdf I just found it. Happy to find fellow Bill Riley, Francois Vernotte and Charles Greenhall in the acknowledgement section. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Oscillators away
Hi Bob, Thanks for making these available to group members. I could make use of either of your Rb, 10 MHz., osc's (17 or 18). I am in need of a high stab osc for my Amateur Radio microwave rover station. These stabilize the Tx/Rx frequencies in the transverters. Best regards, Dave Smith W6TE -Original Message- From: time-nuts On Behalf Of Bob Martin Sent: Wednesday, October 3, 2018 1:30 PM To: Time Nuta Subject: [time-nuts] Oscillators away Time-Nuts, I have a number of oscillators to give away. The link to images, along with a few datasheets is below: https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fapp.box.com%2Fs%2Fhq22jbe3jdfzhfqnot1hxcvjqwdooj6mdata=02%7C01%7C%7Cf13503bc38694d036d9608d6296f220c%7C84df9e7fe9f640afb435%7C1%7C0%7C636741954614227721sdata=6EedT8y4j28OaqaLkJG3RIelonoml90SOhGXfRN4uC0%3Dreserved=0 Note that there are two pages in the Box.com folder. I'm willing to part with them, one or two to a customer, in return for the cost of shipping. For myself, I'd prefer they to go to those who will use them. So, if you want one, please tell me how you plan to incorporate it into your timing system. If you have questions about individual oscillators please send then to the group because the answers can then be shared. The moderator can decide whether this is a viable process. Other than the moderator, please DO NOT not contact me directly for now. In a week or so I'll send a message to the group to begin the request process. This should allow everyone time to consider their needs and possibilities. Some of the devices are valuable and I may share your requests with the group or individuals in the group as a sanity check for your request. Again, please don't contact me directly until everyone has a chance to review the list and I send the post to begin. The selection process will be off-list. Thanks, Bob Martin Oscillator List Osc 1 Efratom EMXO Series Sub-Miniature Military Quartz Crystal Oscillator Old Unit 10MHz sine out - data sheet in Box link Osc2 Efratom EMXO Series Sub-Miniature Military Quartz Crystal Oscillator Old Unit 10.23MHz sine out - data sheet in Box link. Osc3 OCXO Morion MV200 10MHz sine OSC4 OCXO Symmetricom STP2640 LF 10MHz sine Osc5 OCXO Unknown CQE 0140/0020 DOC3098 10MHz sine Size like Milliren 250 series Osc6 OCXO Morion MV200 10MHz sine Attached to mixer based locking circuitry Designed to lock to external reference. If you want it, you will need to show how you plan to use it appropriately. Osc7 OXCO Morion MV83M 5.0MHz sine Mounted in box with regulator and SMA output Osc8 OXCO MTI Milliren 250-0700-B 5.0MHz sine Mounted in cast Bud box with iso-amp to raise output level. Osc9 OXCO MTI Milliren 240-0536-C 16.0MHz square Osc10 OXCO MTI Milliren 240-0551-C 16.0MHz square Osc11 OCXO MTI Milliren 220-0199 32MHz square quant = 4 Output of board is 16MHz square wave 3V into 50 ohms. "Lockoscillator" boards designed to lock automatically to 5 or 10MHz reference. Locking is mixer/integrator based. Used in 5MHz steered DDS's. If you want one you will need to have be explicit regarding your application. Osc 12 OXCO MTI Milliren 220-0199 32.0MHz square quant. = 4 Osc13 OXCO MTI-Milliren 220-0199 32MHz doubled to 64.0MHz Mounted in box with mixer doubler, filters and sine to square wave converter. Osc14 OXCO MTI Milliren 220-0224 77.76MHz square Osc15 VCXO Vectron 155.52MHz PECL out Osc16 TCXO Vectron TC-210-DFC-S5711 100MHz PECL out Data sheet in Box link. Osc17 Symmetricom SA.35m Rubidium 10MHz sine Verified sine out Osc18 Stanford Research PRS10B Rubidium 10MHz sine Verified sine out and PPS Some items were dumpster dived including Osc4, Osc17 and Osc18. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7C%7Cf13503bc38694d036d9608d6296f220c%7C84df9e7fe9f640afb435%7C1%7C0%7C636741954614227721sdata=i5WNN%2Ftohc2PdUo6TZTqsKlmiD6cx%2B5m2OXaUpZspeQ%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Oscillators away
Time-Nuts, I have a number of oscillators to give away. The link to images, along with a few datasheets is below: https://app.box.com/s/hq22jbe3jdfzhfqnot1hxcvjqwdooj6m Note that there are two pages in the Box.com folder. I'm willing to part with them, one or two to a customer, in return for the cost of shipping. For myself, I'd prefer they to go to those who will use them. So, if you want one, please tell me how you plan to incorporate it into your timing system. If you have questions about individual oscillators please send then to the group because the answers can then be shared. The moderator can decide whether this is a viable process. Other than the moderator, please DO NOT not contact me directly for now. In a week or so I'll send a message to the group to begin the request process. This should allow everyone time to consider their needs and possibilities. Some of the devices are valuable and I may share your requests with the group or individuals in the group as a sanity check for your request. Again, please don't contact me directly until everyone has a chance to review the list and I send the post to begin. The selection process will be off-list. Thanks, Bob Martin Oscillator List Osc 1 Efratom EMXO Series Sub-Miniature Military Quartz Crystal Oscillator Old Unit 10MHz sine out - data sheet in Box link Osc2 Efratom EMXO Series Sub-Miniature Military Quartz Crystal Oscillator Old Unit 10.23MHz sine out - data sheet in Box link. Osc3 OCXO Morion MV200 10MHz sine OSC4 OCXO Symmetricom STP2640 LF 10MHz sine Osc5 OCXO Unknown CQE 0140/0020 DOC3098 10MHz sine Size like Milliren 250 series Osc6 OCXO Morion MV200 10MHz sine Attached to mixer based locking circuitry Designed to lock to external reference. If you want it, you will need to show how you plan to use it appropriately. Osc7 OXCO Morion MV83M 5.0MHz sine Mounted in box with regulator and SMA output Osc8 OXCO MTI Milliren 250-0700-B 5.0MHz sine Mounted in cast Bud box with iso-amp to raise output level. Osc9 OXCO MTI Milliren 240-0536-C 16.0MHz square Osc10 OXCO MTI Milliren 240-0551-C 16.0MHz square Osc11 OCXO MTI Milliren 220-0199 32MHz square quant = 4 Output of board is 16MHz square wave 3V into 50 ohms. "Lockoscillator" boards designed to lock automatically to 5 or 10MHz reference. Locking is mixer/integrator based. Used in 5MHz steered DDS's. If you want one you will need to have be explicit regarding your application. Osc 12 OXCO MTI Milliren 220-0199 32.0MHz square quant. = 4 Osc13 OXCO MTI-Milliren 220-0199 32MHz doubled to 64.0MHz Mounted in box with mixer doubler, filters and sine to square wave converter. Osc14 OXCO MTI Milliren 220-0224 77.76MHz square Osc15 VCXO Vectron 155.52MHz PECL out Osc16 TCXO Vectron TC-210-DFC-S5711 100MHz PECL out Data sheet in Box link. Osc17 Symmetricom SA.35m Rubidium 10MHz sine Verified sine out Osc18 Stanford Research PRS10B Rubidium 10MHz sine Verified sine out and PPS Some items were dumpster dived including Osc4, Osc17 and Osc18. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 10 MHz -> 16 MHz
Brian There are 2 parallel feedback paths one tuned to 6MHz and the other tuned to 16MHz. They can either share the same amp or use separate amplifiers. There's a NIST paper on using them to divide by factors other than 2 (e.g. 3, 5 etc). https://tf.nist.gov/general/pdf/1890.pdf Bruce > On 04 October 2018 at 00:54 "Brian, WA1ZMS" wrote: > > > Bruce- > > Does such a dual conjugate regen divider use a single mixer with the BPFs in > parallel? Or are there multiple loops? I'm trying to visualize the > topology. > > I've built a few divide-by-2 regen dividers (both worked very well) but > nothing else. > > -Brian > > > > On Sep 30, 2018, at 4:25 PM, Bruce Griffiths > > wrote: > > > > A low phase noise method is to use a dual conjugate regenerative divider > > with 6MHz and 16Mhz bandpass filters in the feedback loop to produce 16Mhz > > output. > > > > For 12MHz output use 2MHz and 12MHz bandpass filters in the feedback loop. > > > > Bruce > >> On 01 October 2018 at 09:05 Bob kb8tq wrote: > >> > >> > >> Hi > >> > >> If (as originally specified) noise and jitter are not a big deal - there > >> are a lot > >> of chips out there like the ICS570. They are designed to do weird ratio > >> frequency > >> conversions so 10 to 12 or 10 to 16 are trivial for them. The Clockblock > >> board was > >> one way to get it all put together. > >> > >> Bob > >> > >>> On Sep 30, 2018, at 12:05 PM, Gerhard Hoffmann wrote: > >>> > >>> > Am 30.09.2018 um 16:49 schrieb Attila Kinali: > > The simplest way I can think of is the following: > Use a 74LV8154 to divide the 10MHz down to 152.587890625Hz. > Use the capture timer unit of the uC to measure the phase of the > pulse. Use any kind of DAC (internal, external, PWM,...) to steer > the 16MHz VCO. Depending on how fast the timer unit runs, this > will give you something in the order of 10-200ns dead-band. > By choosing the right frequency for the timer unit, one can > get it to "dither" a bit and then use averaging. > > For lower jitter, use one half of a Nutt interpolator > to get the timing difference between the 152Hz signal > and the 16MHz (ie similar to what the SRS FS740 does). > Use something akin Nick Sayer's time-to-amplitude converter > for the fine measurement. > > Same works equally well for 12MHz. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] black holes and list email - Earthlink
On 10/3/18 7:36 AM, John Ackermann N8UR wrote: Yes, the new list provider has their own spam filtering system which is different from (and probably better than) the one I had on the old febo.com. However, it does blacklist addresses from some of the more popular spam-producing ISP servers. As Jim mentioned, the tools seem to be pretty good for getting off the list. It takes about an hour or so..to remove yourself, and you do get a response email saying it's been done. Of course, the problem is that when you resend your mail, it will go through a different MTA, and might have an IP that's been blocked. As a practical matter, looking over those IPs in their logs, it looks like the blacklist provider "gets offended" every few weeks.. John On 10/03/2018 10:25 AM, jimlux wrote: Several times over the past month, I've found that my emails to the list were blocked because they appeared to be junkmail because they came from an IP address (an earthlink MTA) on a black list. Fortunately, you get a bounce message, so you can go to the blacklist and ask it to be removed which typically happens in a few hours. https://spameatingmonkey.com/lookup/209.86.89.62 (or .64, or .69, etc) Or, you can just resend the email, and most likely it goes through a different MTA at Earthlink, which doesn't happen to have it's IP on the list. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] black holes and list email - Earthlink
Yes, the new list provider has their own spam filtering system which is different from (and probably better than) the one I had on the old febo.com. However, it does blacklist addresses from some of the more popular spam-producing ISP servers. As Jim mentioned, the tools seem to be pretty good for getting off the list. John On 10/03/2018 10:25 AM, jimlux wrote: Several times over the past month, I've found that my emails to the list were blocked because they appeared to be junkmail because they came from an IP address (an earthlink MTA) on a black list. Fortunately, you get a bounce message, so you can go to the blacklist and ask it to be removed which typically happens in a few hours. https://spameatingmonkey.com/lookup/209.86.89.62 (or .64, or .69, etc) Or, you can just resend the email, and most likely it goes through a different MTA at Earthlink, which doesn't happen to have it's IP on the list. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] black holes and list email - Earthlink
Several times over the past month, I've found that my emails to the list were blocked because they appeared to be junkmail because they came from an IP address (an earthlink MTA) on a black list. Fortunately, you get a bounce message, so you can go to the blacklist and ask it to be removed which typically happens in a few hours. https://spameatingmonkey.com/lookup/209.86.89.62 (or .64, or .69, etc) Or, you can just resend the email, and most likely it goes through a different MTA at Earthlink, which doesn't happen to have it's IP on the list. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 10 MHz -> 16 MHz
Hi Brian, The typical ones have two amplifier chains in parallel and one mixer. You take the output from the amplifier branch of your liking. The hard part is to tune them to run in synchronous mode and ensure they stay there, or else there is a beat pattern causing excessive jitter over that of the synchronous mode. Cheers, Magnus On 10/3/18 1:54 PM, Brian, WA1ZMS wrote: > Bruce- > > Does such a dual conjugate regen divider use a single mixer with the BPFs in > parallel? Or are there multiple loops? I'm trying to visualize the > topology. > > I've built a few divide-by-2 regen dividers (both worked very well) but > nothing else. > > -Brian > > >> On Sep 30, 2018, at 4:25 PM, Bruce Griffiths >> wrote: >> >> A low phase noise method is to use a dual conjugate regenerative divider >> with 6MHz and 16Mhz bandpass filters in the feedback loop to produce 16Mhz >> output. >> >> For 12MHz output use 2MHz and 12MHz bandpass filters in the feedback loop. >> >> Bruce >>> On 01 October 2018 at 09:05 Bob kb8tq wrote: >>> >>> >>> Hi >>> >>> If (as originally specified) noise and jitter are not a big deal - there >>> are a lot >>> of chips out there like the ICS570. They are designed to do weird ratio >>> frequency >>> conversions so 10 to 12 or 10 to 16 are trivial for them. The Clockblock >>> board was >>> one way to get it all put together. >>> >>> Bob >>> On Sep 30, 2018, at 12:05 PM, Gerhard Hoffmann wrote: > Am 30.09.2018 um 16:49 schrieb Attila Kinali: > > The simplest way I can think of is the following: > Use a 74LV8154 to divide the 10MHz down to 152.587890625Hz. > Use the capture timer unit of the uC to measure the phase of the > pulse. Use any kind of DAC (internal, external, PWM,...) to steer > the 16MHz VCO. Depending on how fast the timer unit runs, this > will give you something in the order of 10-200ns dead-band. > By choosing the right frequency for the timer unit, one can > get it to "dither" a bit and then use averaging. > > For lower jitter, use one half of a Nutt interpolator > to get the timing difference between the 152Hz signal > and the 16MHz (ie similar to what the SRS FS740 does). > Use something akin Nick Sayer's time-to-amplitude converter > for the fine measurement. > > Same works equally well for 12MHz. > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 10MHz standard for comms receivers
The problem with that approach to EMC compliance, is all it does is fool the QP detector in the test/measurement RX. It does nothing to actually reduce the amount of radiated crud, in essence, it's the result of excessive "Bean counting" by the production costs tracking types. Small parts may not radiate that much, but what they are driving could do. Especially if that in turn is driving something over a length of cable! Regards. Dave B. On 02/10/18 17:00, time-nuts-requ...@lists.febo.com wrote: > The main reason for spread spectrum is to make EMI requirements easier to > pass. > Once you get to a small enough part, it really doesn?t generate all that much > EMI internally. > Again, a lot of assumptions get into that. -- Created on and sent from a Unix like PC running and using free and open source software. :: ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Software
On 10/2/18 8:39 PM, Hal Murray wrote: rich...@karlquist.com said: At least for me. I took 1 course in Fortran 50 years ago, and that was the extent of my software education. During my whole career, I have too busy being well paid to design hardware, to have any time left over to learn software. After Fortran was over, there was the Pascal fad, then the C fad, etc, now I guess Python is the latest. Never got involved in any of that. Interesting. All the hardware people I've worked with have been reasonably happy working on software. That may be more common in the digital world. As an example, most people write PAL code as logic equations rather than schematics. It would be interesting to compare the costs of hardware vs software for a big chip project over time. Like most things, "it depends" - here, I'm going to talk about embedded applications (as would be typical for a "time-nuts" widget of some sort) From a "first unit" cost standpoint, in general software is cheaper/easier than FPGA code. It might also be cheaper in hardware on recurring cost basis. Purpose designed processors tend to be faster and lower power, and cheaper than FPGA instantiated processors - ultimately, it takes less sand to make them. There are orders of magnitude more C programmers available than FPGA folks. And there are more of both of them then folks who can design an ASIC. The maturity of the development tools for "software" is far greater than for FPGA and they are cheaper. There are things like documentation generators, debuggers, code analyzers, integrated development environments, and on and on for software. There are multiple vendors for each. In the FPGA world, we're just starting to get analysis capabilities that look for things like clock domain crossings that might cause trouble, decent library management tools. I don't know that there are FPGA equivalents to static code analysis tools like Coverity, CodeSONAR, Semmle, etc. There probably are, but I'm going to bet that they've only been out for a few years, and don't have decades of use behind them like most software tools do. In terms of debugging - whether it's "printf() to the console" or embedded hardware debugger supports like the SPARC/GRMON combination - there's a lot more support for software debugging than in an FPGA. Part of this is that FPGA designs tend to be timing critical - you can't just add a block of code that dumps a bunch of values to a device or file. Tools like ChipScope in the Xilinx family do let you look at some stuff (like having a oscilloscope or logic analyzer in your design) - but the scale and practicality is limited. Just the time required to turn around a new design after fixing a bug is typically faster with software. On the Xilinx Virtex 6 designs I'm working with, resynthesizing the bitstream takes on the order of 30-45 minutes. I haven't had a C compile take that long in years, except when I was compiling some package from source on a Beagle. For most software applications, recompile is a matter of <1 minute (if you're not working in an interactive or JIT language where the time is zero). Maturity of software libraries vs embedded components for FPGAs - for a given function, it is far more likely that there are multiple high quality software implementations than for a FPGA. Look at something like BLAS (for linear algebra) or FFTW - folks have been optimizing numerical libraries for decades - you want a Radix 17 FFT for some reason, and there's probably one out there: in 3 different languages, and either platform indpendent or with a well defined path to optimizing/configuring them for a given platform. In FPGA land, there's some standard building blocks: FFTs, FIR filters,NCOs, various common interfaces (Ethernet, serial port) - but often, there's one or two instances, they're somewhat tied to a specific architecture, and tend to be straightforward implementations. And they're not necessarily cross platform supported - I made the mistake a few years ago of thinking that I could move a digital down converter from Virtex 2 to Virtex 6, but discovered that the IP cores (from Xilinx) used were supported on Virtex 2 but not Virtex 6, and the new cores worked entirely differently. Over a span of a few years, we got virtually no code-reuse - for a very non-sophisticated, non-platform specific design - an oscillator, multiplier, CIC decimator and FIR filter. I can still use the original 10-15 line FORTRAN Radix2 FFT from that IEEE transactions paper in the late 60s without much trouble. An awful lot of people reuse a CRC calculation code for 8 bit microcontrollers that originated in a paper by Aram Perez "Byte-wise CRC Calculations" in IEEE Micro June 1983. It works, why change it. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to
Re: [time-nuts] 10 MHz -> 16 MHz
Bruce- Does such a dual conjugate regen divider use a single mixer with the BPFs in parallel? Or are there multiple loops? I'm trying to visualize the topology. I've built a few divide-by-2 regen dividers (both worked very well) but nothing else. -Brian > On Sep 30, 2018, at 4:25 PM, Bruce Griffiths > wrote: > > A low phase noise method is to use a dual conjugate regenerative divider with > 6MHz and 16Mhz bandpass filters in the feedback loop to produce 16Mhz output. > > For 12MHz output use 2MHz and 12MHz bandpass filters in the feedback loop. > > Bruce >> On 01 October 2018 at 09:05 Bob kb8tq wrote: >> >> >> Hi >> >> If (as originally specified) noise and jitter are not a big deal - there are >> a lot >> of chips out there like the ICS570. They are designed to do weird ratio >> frequency >> conversions so 10 to 12 or 10 to 16 are trivial for them. The Clockblock >> board was >> one way to get it all put together. >> >> Bob >> >>> On Sep 30, 2018, at 12:05 PM, Gerhard Hoffmann wrote: >>> >>> Am 30.09.2018 um 16:49 schrieb Attila Kinali: The simplest way I can think of is the following: Use a 74LV8154 to divide the 10MHz down to 152.587890625Hz. Use the capture timer unit of the uC to measure the phase of the pulse. Use any kind of DAC (internal, external, PWM,...) to steer the 16MHz VCO. Depending on how fast the timer unit runs, this will give you something in the order of 10-200ns dead-band. By choosing the right frequency for the timer unit, one can get it to "dither" a bit and then use averaging. For lower jitter, use one half of a Nutt interpolator to get the timing difference between the 152Hz signal and the 16MHz (ie similar to what the SRS FS740 does). Use something akin Nick Sayer's time-to-amplitude converter for the fine measurement. Same works equally well for 12MHz. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Software
Interesting read. I've been programming since the mid 70's (started with a 2650 and TI59). Graduated in Computer Science and mathematics in 1984, did Honours in Computer Science in 1985. Fast forward decades and I completed a Masters in Astrophysics and a Ph.D. in astrophysics as well. Hate Fortran and Cobol, but can program in 15+ languages and am especially good at C. But, here's something interesting. I picked up R during my Ph.D. I'm now paid professionally to program in R. R is *different*. Every variable is a vector. Even if it's a million rows, a billion rows - that's fine. You have to think differently. Despite all my experience, this is now one of my favourite languages. Statisticians embraced R decades ago. Every statistical test is freely available. Need to do Allan variance? It's done. Need to do a Lomb-Scargle periodogram? Done. Combine that with publication quality plots as well. I think time-nuts should have a serious look at this language. It's available on all platforms for free. RStudio is what you need to look for. Jim On Wed, 3 Oct 2018 at 19:19, ew via time-nuts wrote: > In the seventies at TI most software was done in the Equipment Group and > they did super stuff.We send emails globally and when I traveled I did it > with a Silent 700. Did performance reviews from Norway using rubber cups > and phone handset.Military group was an other story.. Lost our shirt on GPS > because we underestimated the software part 300K code. Was a wake up call > and I was asked to set up a department strictly for code development. Did > focus on management. Never in my professional life had an 8 to 5 job. Just > like Rick, Fortran 50 years ago and focus on the job at hand. Most my > professional life was ion management. After retirement fortunate to meet > Brook Shera and Richard Mc Corkle and still looking for team members to > fill their void.We have some exciting projectsBert Kehren > > In a message dated 10/2/2018 11:40:49 PM Eastern Standard Time, > hmur...@megapathdsl.net writes: > > > rich...@karlquist.com said:> At least for me. I took 1 course in Fortran > 50 years ago, and that was the> extent of my software education. During my > whole career, I have too busy> being well paid to design hardware, to have > any time left over to learn> software. After Fortran was over, there was > the Pascal fad, then the C fad,> etc, now I guess Python is the latest. > Never got involved in any of that. > Interesting. > All the hardware people I've worked with have been reasonably happy > working on software. That may be more common in the digital world. > As an example, most people write PAL code as logic equations rather than > schematics. > It would be interesting to compare the costs of hardware vs software for a > big chip project over time. > > > -- These are my opinions. I hate spam. > > > > ___time-nuts mailing list -- > time-n...@lists.febo.comTo unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow > the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Software
In the seventies at TI most software was done in the Equipment Group and they did super stuff.We send emails globally and when I traveled I did it with a Silent 700. Did performance reviews from Norway using rubber cups and phone handset.Military group was an other story.. Lost our shirt on GPS because we underestimated the software part 300K code. Was a wake up call and I was asked to set up a department strictly for code development. Did focus on management. Never in my professional life had an 8 to 5 job. Just like Rick, Fortran 50 years ago and focus on the job at hand. Most my professional life was ion management. After retirement fortunate to meet Brook Shera and Richard Mc Corkle and still looking for team members to fill their void.We have some exciting projectsBert Kehren In a message dated 10/2/2018 11:40:49 PM Eastern Standard Time, hmur...@megapathdsl.net writes: rich...@karlquist.com said:> At least for me. I took 1 course in Fortran 50 years ago, and that was the> extent of my software education. During my whole career, I have too busy> being well paid to design hardware, to have any time left over to learn> software. After Fortran was over, there was the Pascal fad, then the C fad,> etc, now I guess Python is the latest. Never got involved in any of that. Interesting. All the hardware people I've worked with have been reasonably happy working on software. That may be more common in the digital world. As an example, most people write PAL code as logic equations rather than schematics. It would be interesting to compare the costs of hardware vs software for a big chip project over time. -- These are my opinions. I hate spam. ___time-nuts mailing list -- time-n...@lists.febo.comTo unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
