Re: [time-nuts] Fw: What's the latest correct PICTIC II Mouserproject?-Heathkid
Thanks Stanley, I placed the Mouser order tonight (based on Bob Camp's project he updated). I'm no expert either... but I'd still like to know what are the best options for an enclosure and external connectors... The rest I'll leave up to it all being relative and it is what it is... 73 Brice KA8MAV - Original Message - From: Stanley Reynolds stanley_reyno...@yahoo.com To: time-nuts@febo.com Sent: Saturday, August 14, 2010 12:56 PM Subject: [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. ___ 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 Bob yes that was a point raised by Prof Nat Sokal after I published some data, or rather he pointed out it happened in RF amps. I guess if you take an used PA transistor out of service and measure it you might find the base emitter junction very leaky, but does few mA of leakage matter so much in a low impedance high drive power circuit. Reliability asks does it do the job it was designed for not is it as good as new now Alan G3NYK - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, August 15, 2010 1:33 AM Subject: 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 ___ 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
On 15 August 2010 17:01, Stanley Reynolds stanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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
In Plotter, use the SERIES menu/dropdown to scale the data. As an example for DMTD, I have to multiply the data times 1e-6: Gave the new data a name, in the top of the dropdown, then in this case, enter this formula, in the bottom of the dropdown; X1*1e-6 where X1 is the data WHen it gets thru look at the Column 1 box on the right and you will see a check box with your new data. Uncheck column 1 and Plotter will show the new data. You can now process or save the new data. On 8/15/2010 12:25 AM, John Miles wrote: 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. ___ 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 2:56 PM, J. Forster 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. Right, but the definition of high ft varies over time. Few reasonable designers as recently as 10 years ago would have anticipated the ft of today's CMOS processes. It's also likely they wouldn't have expected their designs to have lasted 10 years, and the vast majority haven't. Oddly enough, it seems like most of the really long life designs are the lower volume ones. These are usally the same ones that won't justify extensive up front analysis and cost unless they are DoD or aerospace applications. 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. But the portion of the discussion that is the root of this branch was precisely about designers being surprised by dramatic and unanticipated changes in component performance. Few rational companies are going to test for parameters in that category. I think we are almost making the same point here. Certainly we agree. My point is that there is an economic tradeoff. There are a number of parameters that are critical to any circuit's operation that it's reasonable to decide are not likely to vary outside critical parameters. It makes no economic sense to test these. -- 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] PicTic Data
Hi If I remember correctly, the inboard clock was chosen to be a good source of noise during the calibration process. It's certainly not a high stability clock. Bob On Aug 15, 2010, at 12:25 AM, John Miles jmi...@pop.net wrote: 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. capture2_freq.gif 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. ___ 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
- Original Message From: Steve Rooke sar10...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sun, August 15, 2010 7:05:40 AM Subject: Re: [time-nuts] PicTic Data On 15 August 2010 17:01, Stanley Reynolds stanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve snip Please do, I would be willing to do the PC boards if the demand makes if possible. 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
On 16 August 2010 01:51, Stanley Reynolds stanley_reyno...@yahoo.com wrote: - Original Message From: Steve Rooke sar10...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sun, August 15, 2010 7:05:40 AM Subject: Re: [time-nuts] PicTic Data On 15 August 2010 17:01, Stanley Reynolds stanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve snip Please do, I would be willing to do the PC boards if the demand makes if possible. I have asked Bill if he is OK with me sharing his design files further and will get back to you. I'd certainly be interested in some PCBs for this. Steve 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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] Fwd: Fwd: PicTic Data
Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. Steve -- Forwarded message -- From: William Riley wjri...@embarqmail.com Date: 16 August 2010 02:32 Subject: Re: Fwd: [time-nuts] PicTic Data To: Steve Rooke sar10...@gmail.com Steve: You are welcome to freely distribute the Small DMTD files. Best regards, Bill W.J. Riley Hamilton Technical Services 650 Distant Island Drive Beaufort, SC 29907-1580 USA Phone: 843-525-6495 Fax: 843-525-0251 E-Mail: b...@wriley.com Web: www.wriley.com -- From: Steve Rooke sar10...@gmail.com Sent: Sunday, August 15, 2010 8:39 AM To: b...@wriley.com Subject: Fwd: [time-nuts] PicTic Data Hello Bill, I have not started on the DMTD project yet as I'm still in the process of building Richard's PICTIC II boards but Stanley Reynolds posted about your DMTD expressing a desire to build them. As I have all the info needed for this, I would be in a position to supply him and anyone else with this data BUT this depends upon your willingness for the distribution of your design to go beyond myself. If you are happy for me to do this, I will, otherwise, i will refrain from doing this? Best regards, Steve -- Forwarded message -- From: Steve Rooke sar10...@gmail.com Date: 16 August 2010 00:05 Subject: Re: [time-nuts] PicTic Data To: Discussion of precise time and frequency measurement time-nuts@febo.com On 15 August 2010 17:01, Stanley Reynolds stanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve 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
Re: [time-nuts] Fwd: Fwd: PicTic Data
In a message dated 15/08/2010 15:53:53 GMT Daylight Time, sar10...@gmail.com writes: I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. -- Hi Steve That's fine with me, thank you. I'm not sure if the list will pass the attachment but sending it direct should be fine. regards Nigel ___ 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] acam TDC chips (was: PicTic Data)
On Sun, 15 Aug 2010 17:57:27 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: An ACAM GP2 evaluation board is available here: http://shop.omegacs.net/ Ignore this link as I omitted to read the fine print Even ignoring the link, the TDC chips by acam seem to be quite nice. Has anyone here designed a complete TDC for time-nuts use using one of their chips? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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] Fwd: Fwd: PicTic Data
Steve, I'm sure there are several folks here with web sites or download areas that could host the files. If no one else raises their hand, I could put them on febo.com. John Steve Rooke said the following on 08/15/2010 10:53 AM: Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. Steve -- Forwarded message -- From: William Rileywjri...@embarqmail.com Date: 16 August 2010 02:32 Subject: Re: Fwd: [time-nuts] PicTic Data To: Steve Rookesar10...@gmail.com Steve: You are welcome to freely distribute the Small DMTD files. Best regards, Bill W.J. Riley Hamilton Technical Services 650 Distant Island Drive Beaufort, SC 29907-1580 USA Phone: 843-525-6495 Fax: 843-525-0251 E-Mail: b...@wriley.com Web: www.wriley.com -- From: Steve Rookesar10...@gmail.com Sent: Sunday, August 15, 2010 8:39 AM To:b...@wriley.com Subject: Fwd: [time-nuts] PicTic Data Hello Bill, I have not started on the DMTD project yet as I'm still in the process of building Richard's PICTIC II boards but Stanley Reynolds posted about your DMTD expressing a desire to build them. As I have all the info needed for this, I would be in a position to supply him and anyone else with this data BUT this depends upon your willingness for the distribution of your design to go beyond myself. If you are happy for me to do this, I will, otherwise, i will refrain from doing this? Best regards, Steve -- Forwarded message -- From: Steve Rookesar10...@gmail.com Date: 16 August 2010 00:05 Subject: Re: [time-nuts] PicTic Data To: Discussion of precise time and frequency measurementtime-nuts@febo.com On 15 August 2010 17:01, Stanley Reynoldsstanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve 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
Re: [time-nuts] Fwd: Fwd: PicTic Data
You can upload it to my web site through the manuals upload page http://www.ko4bb.com/cgi-bin/manuals.pl Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Steve Rooke sar10...@gmail.com Sender: time-nuts-boun...@febo.com Date: Mon, 16 Aug 2010 02:53:28 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] Fwd: Fwd: PicTic Data Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. Steve -- Forwarded message -- From: William Riley wjri...@embarqmail.com Date: 16 August 2010 02:32 Subject: Re: Fwd: [time-nuts] PicTic Data To: Steve Rooke sar10...@gmail.com Steve: You are welcome to freely distribute the Small DMTD files. Best regards, Bill W.J. Riley Hamilton Technical Services 650 Distant Island Drive Beaufort, SC 29907-1580 USA Phone: 843-525-6495 Fax: 843-525-0251 E-Mail: b...@wriley.com Web: www.wriley.com -- From: Steve Rooke sar10...@gmail.com Sent: Sunday, August 15, 2010 8:39 AM To: b...@wriley.com Subject: Fwd: [time-nuts] PicTic Data Hello Bill, I have not started on the DMTD project yet as I'm still in the process of building Richard's PICTIC II boards but Stanley Reynolds posted about your DMTD expressing a desire to build them. As I have all the info needed for this, I would be in a position to supply him and anyone else with this data BUT this depends upon your willingness for the distribution of your design to go beyond myself. If you are happy for me to do this, I will, otherwise, i will refrain from doing this? Best regards, Steve -- Forwarded message -- From: Steve Rooke sar10...@gmail.com Date: 16 August 2010 00:05 Subject: Re: [time-nuts] PicTic Data To: Discussion of precise time and frequency measurement time-nuts@febo.com On 15 August 2010 17:01, Stanley Reynolds stanley_reyno...@yahoo.com 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. I have been speaking to Bill Riley about doing this myself and he has sent me all the board designs, software, etc. to enable one to be built. I can ask him if he is OK if I distribute this if you wish. Steve 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
Re: [time-nuts] PicTic Data
I really like using small individual cheap coolers; the ones that hold a six-pack. Stick the stuff in. Use wire-wrap wire and small coax to get signals and power in and out... Don Stanley Reynolds 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. -- 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 Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] Fwd: Fwd: PicTic Data
Files here : www.n4iqt.com/BillRiley removed the spaces in the file names but they are still a mix of upper and lower case still checking them to make sure they are OK 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] Fwd: Fwd: PicTic Data
Steve Rooke wrote: Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. I can host the file if needed, let me know. ___ 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] acam TDC chips (was: PicTic Data)
I've just sent for a quote for one off. The site simply sucks! There is NO information as to how to get your hands on a small sample, a breakout board, or anything else that a design engineer would need to make a decision...You can get some software and data sheets, or what looks to be a horribly expensive test box. I was thinking this chip might make a useful replacement for my 5370A units in my mad race to replace all the '80's and earlier HP stuff with PC based instruments... Don Attila Kinali On Sun, 15 Aug 2010 17:57:27 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: An ACAM GP2 evaluation board is available here: http://shop.omegacs.net/ Ignore this link as I omitted to read the fine print Even ignoring the link, the TDC chips by acam seem to be quite nice. Has anyone here designed a complete TDC for time-nuts use using one of their chips? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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. -- 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 Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] Fwd: Fwd: PicTic Data
Files here www.n4iqt.com/BillRiley If you rename the PCB and or the SCH files you will need to relink them in the expressPCB program. The mixer board has a netlink warning but this maybe on purpose as it is with the ground and maybe the isolation mentioned in the notes. Stanley - Original Message From: jimlux jim...@earthlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sun, August 15, 2010 11:37:07 AM Subject: Re: [time-nuts] Fwd: Fwd: PicTic Data Steve Rooke wrote: Stanley and Nigel, I have received the go ahead to distribute the Small DMTD project files from Bill. It is in the form of a 500k zip so how do we want to play this? For a start, Gmail will not let me send .exe files, even though they are inside a zip file and I'm not putting them into a password encrypted file to circumvent this so I'll send the archive with the extension changed to .xxx. If you don't know how to change that back to .zip may I suggest you contact Mr Gates and tell him that his method of file typing sucks and is a noddy system fit only for Toytown. I can host the file if needed, let me know. ___ 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] acam TDC chips (was: PicTic Data)
I'll see what they say, Stanley. I think I'll put one (if I can get it) on a Schmartboard and go from there. I still wonder why this and other companies seem so reluctant to sell you something :-) Don Stanley Reynolds They were very helpful to me. But cost is on the high side till you factor in the low volume they probably have. I would be interested in your old HP stuff :-) Stanley - Original Message From: Don Latham d...@montana.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sun, August 15, 2010 11:51:54 AM Subject: Re: [time-nuts] acam TDC chips (was: PicTic Data) I've just sent for a quote for one off. The site simply sucks! There is NO information as to how to get your hands on a small sample, a breakout board, or anything else that a design engineer would need to make a decision...You can get some software and data sheets, or what looks to be a horribly expensive test box. I was thinking this chip might make a useful replacement for my 5370A units in my mad race to replace all the '80's and earlier HP stuff with PC based instruments... Don Attila Kinali On Sun, 15 Aug 2010 17:57:27 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: An ACAM GP2 evaluation board is available here: http://shop.omegacs.net/ Ignore this link as I omitted to read the fine print Even ignoring the link, the TDC chips by acam seem to be quite nice. Has anyone here designed a complete TDC for time-nuts use using one of their chips? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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. -- 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 Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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. -- 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 Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] OT: leaching was, Alternative time interval interpolation technique
On Sun, 15 Aug 2010 14:59:43 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: 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 A quick skimming over the error analysis Panek made, suggests that the jitter of the clock source is the biggest contributor to measurement errors. But he never says how a clock source with such a low jitter is build. Although he references a few times a module build by Josef Kölbl of the Fachhochschule Deggendorf, there is no description available what kind of device that is. Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] acam TDC chips
Hello, I purchased 5 pcs TDC-GP2 from them about 3yr ago, but never had time to put them to work. My intention was to discipline a Rb to GPS, but I ended purchasing a Thunderbolt :) Price then was 15 EUR/unit (1 to 9 pcs), 14.50 EUR/unit (10pcs), plus shipping, so not unexpensive, but not unaffordable. In any case, I don't remember any difficulty to purchase from them. If it is of some utility, the contact person that I communicated with was Mr. Klaus Weser, kwe...@acam.de Best regards, Javier I'll see what they say, Stanley. I think I'll put one (if I can get it) on a Schmartboard and go from there. I still wonder why this and other companies seem so reluctant to sell you something :-) I'd be interested in this too. If it helps, i could call and talk to them directly. Being in the same language zone might help ;-) Attila Kinali -- 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] acam TDC chips
Thanks, Javier. Good to know. These look to be a very useful chip. If I get one or two, I'll try using one with an Arduino, my current favorite micro. Don Javier Herrero Hello, I purchased 5 pcs TDC-GP2 from them about 3yr ago, but never had time to put them to work. My intention was to discipline a Rb to GPS, but I ended purchasing a Thunderbolt :) Price then was 15 EUR/unit (1 to 9 pcs), 14.50 EUR/unit (10pcs), plus shipping, so not unexpensive, but not unaffordable. In any case, I don't remember any difficulty to purchase from them. If it is of some utility, the contact person that I communicated with was Mr. Klaus Weser, kwe...@acam.de Best regards, Javier I'll see what they say, Stanley. I think I'll put one (if I can get it) on a Schmartboard and go from there. I still wonder why this and other companies seem so reluctant to sell you something :-) I'd be interested in this too. If it helps, i could call and talk to them directly. Being in the same language zone might help ;-) Attila Kinali -- 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. -- 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 Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] OT: leaching was, Alternative time interval interpolation technique
Attila Kinali wrote: On Sun, 15 Aug 2010 14:59:43 +1200 Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: 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 A quick skimming over the error analysis Panek made, suggests that the jitter of the clock source is the biggest contributor to measurement errors. But he never says how a clock source with such a low jitter is build. Although he references a few times a module build by Josef Kölbl of the Fachhochschule Deggendorf, there is no description available what kind of device that is. Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? Attila Kinali Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. 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] Small DMTD project PCBs Group Buy
Any interest in boards at 8 USD each as before ? The project would require 2 or 3 pictic boards, 2 mixer boards, and 1 DDS board. 5 boards plus shipping about 47.50 usd Please email me off list with your interest. I not sure if using the pictic II vs I board will present problems for the software. Would also like to workout any changes to the DDS or Mixer Boards before I place the order. Yes I still have PICTIC II boards from the first order and other parts for them. 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
It depends on whether the leakage continues to rise or stabilizes after a burn in period. -John Hi Bob yes that was a point raised by Prof Nat Sokal after I published some data, or rather he pointed out it happened in RF amps. I guess if you take an used PA transistor out of service and measure it you might find the base emitter junction very leaky, but does few mA of leakage matter so much in a low impedance high drive power circuit. Reliability asks does it do the job it was designed for not is it as good as new now Alan G3NYK - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, August 15, 2010 1:33 AM Subject: 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 ___ 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
J. Forster wrote: It depends on whether the leakage continues to rise or stabilizes after a burn in period. -John Hi Bob yes that was a point raised by Prof Nat Sokal after I published some data, or rather he pointed out it happened in RF amps. I guess if you take an used PA transistor out of service and measure it you might find the base emitter junction very leaky, but does few mA of leakage matter so much in a low impedance high drive power circuit. Reliability asks does it do the job it was designed for not is it as good as new now Alan We get into the argument about still works ok in the circuit vs doesn't meet databook specs all the time at work. To some folks, not meet datasheet = failure, while if you have a circuit that needs a gain of 10, and the part has a gain of 1000, and degrades to 500, it's hardly failed. And rarely, do you have the budget or time to do a real life test to prove it experimentally. In radiation environments, it's more of a continuous aging effect.. more dose, more leakage. And what drives the conflict between designer and reliability guys is that the effect isn't particularly predictable, particularly between lots (because it's not something controlled in the process) (which makes life testing all that much more fun) ___ 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] Low jitter oscillators
Hi Attila, note that manufacturers are kind of cheating when they say things like 0.2ps rms jitter - see the N.S. appnotes below for example. This is mostly calculated from phase noise, with typical bandwidth limits of 20Hz to 20MHz or less. So what happens below 20Hz or above 20MHz offset is usually ignored in this number by filtering it out.. bye, Said In a message dated 8/15/2010 13:38:24 Pacific Daylight Time, charles_steinm...@lavabit.com writes: Attila wrote: Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? As Bruce noted, low jitter oscillators are available from any number of sources. If you want to try rolling your own, here are a few sources to start you off: http://contentdm.lib.byu.edu/ETD/image/etd369.pdf http://link.aip.org/link/?ELLEAK/34/2024/1 http://www.national.com/vcm/NSC_Content/Files/en_US/Timing/LMK04000_ProdBrie f.pdf http://www.national.com/an/AN/AN-1939.pdf http://www.national.com/an/AN/AN-1910.pdf I'm sure others will have many more suggestions. Best regards, Charles ___ 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] Low jitter oscillators
Hi The bandwidths chosen generally have roots in a telcom spec. Infinite bandwidth generally equates to infinite jitter. You have to restrict it somehow. Bob On Aug 15, 2010, at 8:18 PM, saidj...@aol.com wrote: Hi Attila, note that manufacturers are kind of cheating when they say things like 0.2ps rms jitter - see the N.S. appnotes below for example. This is mostly calculated from phase noise, with typical bandwidth limits of 20Hz to 20MHz or less. So what happens below 20Hz or above 20MHz offset is usually ignored in this number by filtering it out.. bye, Said In a message dated 8/15/2010 13:38:24 Pacific Daylight Time, charles_steinm...@lavabit.com writes: Attila wrote: Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? As Bruce noted, low jitter oscillators are available from any number of sources. If you want to try rolling your own, here are a few sources to start you off: http://contentdm.lib.byu.edu/ETD/image/etd369.pdf http://link.aip.org/link/?ELLEAK/34/2024/1 http://www.national.com/vcm/NSC_Content/Files/en_US/Timing/LMK04000_ProdBrie f.pdf http://www.national.com/an/AN/AN-1939.pdf http://www.national.com/an/AN/AN-1910.pdf I'm sure others will have many more suggestions. Best regards, Charles ___ 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 08/16/2010 02:16 AM, jimlux wrote: We get into the argument about still works ok in the circuit vs doesn't meet databook specs all the time at work. To some folks, not meet datasheet = failure, while if you have a circuit that needs a gain of 10, and the part has a gain of 1000, and degrades to 500, it's hardly failed. And rarely, do you have the budget or time to do a real life test to prove it experimentally. In radiation environments, it's more of a continuous aging effect.. more dose, more leakage. And what drives the conflict between designer and reliability guys is that the effect isn't particularly predictable, particularly between lots (because it's not something controlled in the process) (which makes life testing all that much more fun) But armed with the knowledge of what parameters do degrade, you may do simulations of various grades of degradation and show that with the current knowledge of degradation and assumptions on its effects and degrees, it is reasonable to expect functionality. Right? Simulation can be off assistance, if used wisely... (or a tool of self deception if not used wisely) 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] Low jitter oscillators
I have data on a relatively easy to reproduce programmable source consisting of a Wenzel Sprinter OXCO @ 100MHZ followed by an AD9513 Eval board. This pair yields 1ps rms jitter using a measurement bandwidth from 1Hz to 5MHz. Beyond 5MHz the noise floor is -166dBc/Hz. This result was measured on an Agilent E5052B and confirmed (with significant uncertainty) on a DTS2075 via rms calculation based on the DTS measured jitter floor of 2.1ps rms. These are all cycle to cycle measurements. Certainly, optimized OXCOs will perform much better than this, but it was good enough for my needs. I have informal communication within Agilent that the low jitter 10811 devices exhibit 180fs rms jitter routinely. Pete Rawson ___ 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 23:49 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: At 19:01 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: 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. That's not a bad idea (the recent Simulation thread notwithstanding), I'll see if I can find the time to cobble something together. Suggested procedure: - Assume perfect ADC buffers (not unrealistic, some of the MCP6xxx parts have enough GBW and slew rate), and a 2V ADC reference. - Independent variables: * Number of ADC bits (8...12) * ADC input noise (model as AWGN, vary over 0...10LSB) * ADC aperture jitter (AWGN, 0...2ns) * ADC sample rate (1 or 2 MSPS) * Ramp rate (0.1/0.2/0.5/1V/us, to be varied by changing C1 and only C1) * For Circuit 3: Difference between ramp rates (0...10%, again through C1) - Have LTSpice generate a simulated ramp with enough time resolution (say 100ps), do linear interpolation if needed. - For each combination of independent variables: * Generate simulated ramp(s) * Run a realistic number of -100ns/0ns/+100ns calibrations (call it 100 runs) * Sweep the simulated offset from -500ns to 500ns in 1ns steps * For each simulated offset, do a few thousand measurement runs * Collect statistics - Plot RMS and 90%-limits for the recorded data. That should keep all eight cores busy for a day or so. Does that sound like a workable plan? If I feel up to it, I'll see if I can add the simple RC-filter to the mix, although I'm less confident about doing proper a priori weighed error curve fitting on that than on the simple linear ramps. (I'd like to look at slower ramps/ADCs because the more I think about it the more I prefer the ADuC7024, with +/-1LSB INL @1MSPS over the +/-6LSB @2MSPS of the ATXMega. An added bonus of the ADuC is that it has a small on-chip PLA, which might allow me to do without a CPLD). In the case of the 3 diode TAC devised by Kasper Pedersen some compensation of diode capacitance modulation occurs if the diodes are matched. Hadn't seen that one yet. Looks interesting, but losing another two diode drops on top of the current source's compliance range may be a bit too tight for 3.3V operation. I've tried it in the simulator and on the bench, and it works quite well. I'll check again, but thats not consistent with what I found with a simulated 1mA current source. As I mentioned a few messages ago the ramp becomes much more linear (due to swamping of parasitics) when the current and the capacitor are increased tenfold. Tried it again on the bench with the values as in the attached sim file (SMD parts dead bug on a ground plane, with a FDV301N in series with a 10R resistor shorting the capacitor, and a resistor to set the current), and as far as I can eyeball it on my 100MHz scope it works as advertised. Not that a scope check is the last word in linearity, but at least there are no gross discrepancies with the simulator's results. Having said that, I'm open for other suggestions wrt the current source. JD Monte Carlo B. -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ mirror_4tran.asc Description: Binary data ___ 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
Hi I think that adding ADC zero and gain drift would be a good idea. Bob On Aug 15, 2010, at 9:19 PM, J.D. Bakker j...@lartmaker.nl wrote: At 23:49 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: At 19:01 +1200 14-08-2010, Bruce Griffiths wrote: J.D. Bakker wrote: 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. That's not a bad idea (the recent Simulation thread notwithstanding), I'll see if I can find the time to cobble something together. Suggested procedure: - Assume perfect ADC buffers (not unrealistic, some of the MCP6xxx parts have enough GBW and slew rate), and a 2V ADC reference. - Independent variables: * Number of ADC bits (8...12) * ADC input noise (model as AWGN, vary over 0...10LSB) * ADC aperture jitter (AWGN, 0...2ns) * ADC sample rate (1 or 2 MSPS) * Ramp rate (0.1/0.2/0.5/1V/us, to be varied by changing C1 and only C1) * For Circuit 3: Difference between ramp rates (0...10%, again through C1) - Have LTSpice generate a simulated ramp with enough time resolution (say 100ps), do linear interpolation if needed. - For each combination of independent variables: * Generate simulated ramp(s) * Run a realistic number of -100ns/0ns/+100ns calibrations (call it 100 runs) * Sweep the simulated offset from -500ns to 500ns in 1ns steps * For each simulated offset, do a few thousand measurement runs * Collect statistics - Plot RMS and 90%-limits for the recorded data. That should keep all eight cores busy for a day or so. Does that sound like a workable plan? If I feel up to it, I'll see if I can add the simple RC-filter to the mix, although I'm less confident about doing proper a priori weighed error curve fitting on that than on the simple linear ramps. (I'd like to look at slower ramps/ADCs because the more I think about it the more I prefer the ADuC7024, with +/-1LSB INL @1MSPS over the +/-6LSB @2MSPS of the ATXMega. An added bonus of the ADuC is that it has a small on-chip PLA, which might allow me to do without a CPLD). In the case of the 3 diode TAC devised by Kasper Pedersen some compensation of diode capacitance modulation occurs if the diodes are matched. Hadn't seen that one yet. Looks interesting, but losing another two diode drops on top of the current source's compliance range may be a bit too tight for 3.3V operation. I've tried it in the simulator and on the bench, and it works quite well. I'll check again, but thats not consistent with what I found with a simulated 1mA current source. As I mentioned a few messages ago the ramp becomes much more linear (due to swamping of parasitics) when the current and the capacitor are increased tenfold. Tried it again on the bench with the values as in the attached sim file (SMD parts dead bug on a ground plane, with a FDV301N in series with a 10R resistor shorting the capacitor, and a resistor to set the current), and as far as I can eyeball it on my 100MHz scope it works as advertised. Not that a scope check is the last word in linearity, but at least there are no gross discrepancies with the simulator's results. Having said that, I'm open for other suggestions wrt the current source. JD Monte Carlo B. -- LART. 250 MIPS under one Watt. Free hardware design files. http://www.lartmaker.nl/ mirror_4tran.asc ___ 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] Low jitter oscillators
Hi Bob, Agreed that at a minimum the instrument will restrict the bandwidth due to it's own bandwidth limitations, and some (like the Wavecrest units) go up to 1GHz or more. But many vendors claim sub 1ps jitter on low cost oscillators, and don't specify what bandwidth was used to measure this jitter. That would be like giving phase noise in dBc without also specifying the /Hz, and then every vendor using their own internal bandwidth definitions to make their phase noise claims.. Sometimes I think vendors assume that E5052A units are being used everywhere to measure jitter. bye, Said In a message dated 8/15/2010 17:34:09 Pacific Daylight Time, li...@rtty.us writes: Hi The bandwidths chosen generally have roots in a telcom spec. Infinite bandwidth generally equates to infinite jitter. You have to restrict it somehow. 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] Small DMTD project PCBs Group Buy
Just a note, Arrow has a bunch of the dread 74AC175P and will ship small orders... Don - Original Message - From: Stanley Reynolds stanley_reyno...@yahoo.com To: time-nuts@febo.com Sent: Sunday, August 15, 2010 2:14 PM Subject: [time-nuts] Small DMTD project PCBs Group Buy Any interest in boards at 8 USD each as before ? The project would require 2 or 3 pictic boards, 2 mixer boards, and 1 DDS board. 5 boards plus shipping about 47.50 usd Please email me off list with your interest. I not sure if using the pictic II vs I board will present problems for the software. Would also like to workout any changes to the DDS or Mixer Boards before I place the order. Yes I still have PICTIC II boards from the first order and other parts for them. 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.
