Re: [time-nuts] Range of Sawtooth values?
albertson.ch...@gmail.com said: The M12 user manual hints at why, they say the newer receiver runs on a faster internal clock. Roughly, it's going to be within 1/2 clock cycle. If newer units have faster clocks, the peak-peak sawtooth should be smaller. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Range of Sawtooth values?
Hi If you watch long enough and know the clock frequency, you will find corrections over the entire period of the clock. In most modules that shows up as a +/- 1/2 clock period correction. Bob On Mar 10, 2014, at 2:03 AM, Hal Murray hmur...@megapathdsl.net wrote: albertson.ch...@gmail.com said: The M12 user manual hints at why, they say the newer receiver runs on a faster internal clock. Roughly, it's going to be within 1/2 clock cycle. If newer units have faster clocks, the peak-peak sawtooth should be smaller. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] ADEV from phase or frequency measurement
Even if the -3dB were an issue, I'd have much more faith in a clear, passive resistor network than in a complex amplifier with all it's unknown non linear characteristics, temperature dependent time delays, noise sources, etc., etc. This simple home made network is a useful, manageable gadget. Volker Bob Camp li...@rtty.us hat am 10. März 2014 um 01:47 geschrieben: Hi So far, I have not found the 3db lost in a a passive splitter to be a problem with anything I have played with. With proper termination , they seem to be a good thing to use. Bob On Mar 9, 2014, at 7:55 PM, Volker Esper ail...@t-online.de wrote: Bob, I sometimes indeed do arc welding, as well as forging... But that's another story. When waiting for an ADEV measurement I sit still, trying not to move a millimeter. Seriously, I try to avoid any rf noise, e.g. ham radio, any airflow, any temperature change. I log supply voltages and check, if there's anything odd. I avoid any switching supply. I regularely check, if any switching voltage regulator (TV, monitors, PC,...) disturbs my rf ether... As the legends of my plots tell, I do use a passive splitter to get two similar signals (start and stop) for phase measurement. But I haven't used it for splitting the 10MHz for frequency measurement (reference and input). Lower level is a concern, since it increases phase jitter. Volker Am 09.03.2014 23:32, schrieb Bob Camp: Hi Do you routinely do arc welding while waiting for an ADEV plot to finish :)… (I drink beer, but not everybody is into that …) You might consider trying a passive splitter on one of the outputs of the GPSDO. There aren’t many ways they will mess up a signal other than by dropping it’s level. If level is a concern then indeed they could be an issue. Bob On Mar 9, 2014, at 6:17 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 09/03/14 22:36, Volker Esper wrote: Am 09.03.2014 19:46, schrieb Magnus Danielson: On 04/03/14 01:05, Volker Esper wrote: Am 03.03.2014 23:04, schrieb Magnus Danielson: Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external reference; signal source Nortel/Trimble GPSTM (GPSDO) 10MHz output Enclosed two plots (SW: Plotter): - one is sigma(tau) calculated from phase samples (SR620 TIME mode), - the other one is sigma(tau) from frequency data (SR620 FREQ mode) Whole equipment had a power up time of several days/weeks. Room temperature was stable over both measurements (within about 2 degrees C). The SR620 uses a bit different path through the logic when doing TI and FREQ measurements. The frequency measurement has a feature that means that the time error between start and stop signal needs to be calibrated out. This can be done using the calibration routines given in the manual. This should not affect the ADEV measure, but as a precaution. Try doing a pair of noise-floor measurements. That is, feed the reference 10 MHz to the A input for the frequency noise measurement. Then, for the TI noise-floor measurement, put a T on the A input, put it in high-Z mode and then use a 1 m cable to put the signal onto the B input which is terminating. You indeed have a higher level. Your initial shape makes me wonder. I would really like to get the TimeLab measurement files and eye-ball them closer. If you plot the phase or frequency, it may be easier to spot systematic wobbles. TDEV would also help, as it provides a general *tau scaling to the ADEV plot. 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. I already did these measurements, I stick the plots at this posting. - The plot with the long file name shows frequency mode measurement: 10MHz external reference put into channel A. - ...Plot2 shows a phase measurement, where I fed the reference signal via a home made 50 ohms splitter into both input channels. (I prefer feeding the channels symmetrically) Both plots show linear negative gradients, but the phase plot is steeper. The frequency plot transitions into a horizontal at about 1000s. The 1/sqrt(tau) curve is higher than the background noise of the counter. That flicker phase noise is more typical of a buffer or source than of the counter. For shorter taus I would expect the white noise to dominate. I'm just surprised about the level of flicker phase noise. What is the source? 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. Source in both cases is an HP Z3805 GPSDO. I didn't insert an
Re: [time-nuts] ADEV from phase or frequency measurement
Hi I’ve played with both the 6 db loss resistive splitters and the transformer based 3 db loss splitters. They both seem to be fine for splitting precision 10 MHz signals. For a while I avoided the transformer based parts, but not for any reason I could prove. Bob On Mar 10, 2014, at 7:41 AM, Volker Esper ail...@t-online.de wrote: Even if the -3dB were an issue, I'd have much more faith in a clear, passive resistor network than in a complex amplifier with all it's unknown non linear characteristics, temperature dependent time delays, noise sources, etc., etc. This simple home made network is a useful, manageable gadget. Volker Bob Camp li...@rtty.us hat am 10. März 2014 um 01:47 geschrieben: Hi So far, I have not found the 3db lost in a a passive splitter to be a problem with anything I have played with. With proper termination , they seem to be a good thing to use. Bob On Mar 9, 2014, at 7:55 PM, Volker Esper ail...@t-online.de wrote: Bob, I sometimes indeed do arc welding, as well as forging... But that's another story. When waiting for an ADEV measurement I sit still, trying not to move a millimeter. Seriously, I try to avoid any rf noise, e.g. ham radio, any airflow, any temperature change. I log supply voltages and check, if there's anything odd. I avoid any switching supply. I regularely check, if any switching voltage regulator (TV, monitors, PC,...) disturbs my rf ether... As the legends of my plots tell, I do use a passive splitter to get two similar signals (start and stop) for phase measurement. But I haven't used it for splitting the 10MHz for frequency measurement (reference and input). Lower level is a concern, since it increases phase jitter. Volker Am 09.03.2014 23:32, schrieb Bob Camp: Hi Do you routinely do arc welding while waiting for an ADEV plot to finish :)… (I drink beer, but not everybody is into that …) You might consider trying a passive splitter on one of the outputs of the GPSDO. There aren’t many ways they will mess up a signal other than by dropping it’s level. If level is a concern then indeed they could be an issue. Bob On Mar 9, 2014, at 6:17 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 09/03/14 22:36, Volker Esper wrote: Am 09.03.2014 19:46, schrieb Magnus Danielson: On 04/03/14 01:05, Volker Esper wrote: Am 03.03.2014 23:04, schrieb Magnus Danielson: Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external reference; signal source Nortel/Trimble GPSTM (GPSDO) 10MHz output Enclosed two plots (SW: Plotter): - one is sigma(tau) calculated from phase samples (SR620 TIME mode), - the other one is sigma(tau) from frequency data (SR620 FREQ mode) Whole equipment had a power up time of several days/weeks. Room temperature was stable over both measurements (within about 2 degrees C). The SR620 uses a bit different path through the logic when doing TI and FREQ measurements. The frequency measurement has a feature that means that the time error between start and stop signal needs to be calibrated out. This can be done using the calibration routines given in the manual. This should not affect the ADEV measure, but as a precaution. Try doing a pair of noise-floor measurements. That is, feed the reference 10 MHz to the A input for the frequency noise measurement. Then, for the TI noise-floor measurement, put a T on the A input, put it in high-Z mode and then use a 1 m cable to put the signal onto the B input which is terminating. You indeed have a higher level. Your initial shape makes me wonder. I would really like to get the TimeLab measurement files and eye-ball them closer. If you plot the phase or frequency, it may be easier to spot systematic wobbles. TDEV would also help, as it provides a general *tau scaling to the ADEV plot. 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. I already did these measurements, I stick the plots at this posting. - The plot with the long file name shows frequency mode measurement: 10MHz external reference put into channel A. - ...Plot2 shows a phase measurement, where I fed the reference signal via a home made 50 ohms splitter into both input channels. (I prefer feeding the channels symmetrically) Both plots show linear negative gradients, but the phase plot is steeper. The frequency plot transitions into a horizontal at about 1000s. The 1/sqrt(tau) curve is higher than the background noise of the counter. That flicker phase noise is more typical of a buffer or source than of the counter. For shorter taus I would expect the white noise to dominate. I'm just surprised about the level of flicker phase noise. What is the source? Cheers, Magnus
Re: [time-nuts] Finding a spare part for HP5370B
It's part No 05370-20206, no longer available from Agilent. I don't think you will find one easily. Best bet is to buy some plastic and make one. The proper plastic filter material is polarised to increase contrast but thin red acrylic sheet will do OK. masking the annciators may be tricky. Try a black on clear label maker. A professional one should be able to do the required mirrored (you will be sticking it to the inside of the window) and negative (clear on black) label. HTH, Robert G8RPI. From: Pascual Arbona Lopez p.arb...@securimar.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, 8 March 2014, 7:21 Subject: [time-nuts] Finding a spare part for HP5370B Hello! I have been given an HP5370B; I have checked it and it seems to work fine, but unfortunately its missing the red plastic in the display window. If anyone has one of these equipments for spare parts, I would be very grateful if I can buy this part. Please contact me off list if you can help at p.arb...@securimar.com Many thanks P. Arbona ___ 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] How to measure phase noise of HCMOS oscillators?
A while a go i bought some low phase noise Crystek CVHD-950 and now I want to meas the phase noise of the oscillators. Is it best to try to impedance match the output signal and filter and amplify the hcmos before i feed it in to the phase detector? or Just hope that the signal is high enough to drive the mixer? What about all the harmonics? Does it alter the phase noise result? /Anders ___ 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] HP 10811 - 60165 Info Request
I have acquired one of these double oven oscillators. Seems like a useful thing. Need info on pin outs, and operating voltages. Also any other useful information or links to same would be appreciated. Please reply off list with any files of specs etc to my email - johncr...@aol.com All help appreciated. Best regards to all john c roos k6iql ___ 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] Modeling vs reality question re my TIC
Fellow Timenuts: I'm trying to square reality with the modeling that I did, and nothing makes sense. When I modeled the result of just my 2.4K resistor with the caps and resistor the PIC datasheet says it has in it, there's no relationship. The model says I'll get millivolts out. Here's how I calculate what I'm actually getting: ADC VRef is 2.5V 10-bit ADC = 1024 positions Max ADC from TIC = 975 975/1024*2.5 = 2.38V Max TIC value Min ADC from TIC = 293 293/1024*2.5 = 0.715V Min TIC value A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated. Bob - AE6RV ___ 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] Modeling vs reality question re my TIC
b...@evoria.net said: A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated. My quick guess is a problem reading the specs. 120 pF is probably an internal cap, 20 pF seems reasonable for the cap on a pin. Lots of people would get unhappy if the pin cap was 120 pF. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 10811 - 60165 Info Request
1 - BRN Oscillator Return (Com) 2 - RED Oscillator Power (+12V) 3 - ORG Oven Monitor Return (Com) 4 - YEL Oven Monitor Output 5 - GRN Oven Power (+18-24V) 6 - BLU Oven Return (Com) Thomas Knox To: time-nuts@febo.com From: johncr...@aol.com Date: Mon, 10 Mar 2014 14:17:58 -0400 Subject: [time-nuts] HP 10811 - 60165 Info Request I have acquired one of these double oven oscillators. Seems like a useful thing. Need info on pin outs, and operating voltages. Also any other useful information or links to same would be appreciated. Please reply off list with any files of specs etc to my email - johncr...@aol.com All help appreciated. Best regards to all john c roos k6iql ___ 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] HP 10811 - 60165 Info Request
Thanks to TVB for hosting this manual containing info for most models of the venerable 10811. http://www.leapsecond.com/museum/10811a/10811a.pdf Thomas Knox To: time-nuts@febo.com From: johncr...@aol.com Date: Mon, 10 Mar 2014 14:17:58 -0400 Subject: [time-nuts] HP 10811 - 60165 Info Request I have acquired one of these double oven oscillators. Seems like a useful thing. Need info on pin outs, and operating voltages. Also any other useful information or links to same would be appreciated. Please reply off list with any files of specs etc to my email - johncr...@aol.com All help appreciated. Best regards to all john c roos k6iql ___ 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] Modeling vs reality question re my TIC
On Mon, Mar 10, 2014 at 12:12 PM, Bob Stewart b...@evoria.net wrote: A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated. Could it be a software issue? 20pf seems about right for a normal input pin in a typical chip. They all have diodes protecting from static and 20 pf seems like what I'd expect. You say there is an internal 120 pf cap inside the PIC? If so you'd need to connect that. It may be that you are not doing that correctly or at the time you think you are. I'm guessing and we'd need both the spec sheet and your code to know for sure. -- Chris Albertson Redondo Beach, California ___ 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] Modeling vs reality question re my TIC
Hi Chris, I don't think it's a software issue, as the voltage doubled when I halved the VRef - which is what would be expected. Also, the voltages tracked the 5334B when I still had it connected, except that the TIC seems more precise and less noisy. Then again, the 5334B was being fed with 8 ft of RG-58U. What I'm seeing with the TIC is exactly what I would expect to see, only better, if that makes any sense. Maybe the LTSpiceIV models are where the problem lies. Let me clarify the caps. This is an 18F2220 PIC. The pin cap is 5pf. There is an internal CHOLD in the ADC which is listed as 120pf. Here is a screenshot of the relevant page. http://www.evoria.net/AE6RV/TIC/ADC.png Bob From: Chris Albertson albertson.ch...@gmail.com To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 10, 2014 3:26 PM Subject: Re: [time-nuts] Modeling vs reality question re my TIC On Mon, Mar 10, 2014 at 12:12 PM, Bob Stewart b...@evoria.net wrote: A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated. Could it be a software issue? 20pf seems about right for a normal input pin in a typical chip. They all have diodes protecting from static and 20 pf seems like what I'd expect. You say there is an internal 120 pf cap inside the PIC? If so you'd need to connect that. It may be that you are not doing that correctly or at the time you think you are. I'm guessing and we'd need both the spec sheet and your code to know for sure. -- Chris Albertson Redondo Beach, California ___ 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] Modeling vs reality question re my TIC
Metastability in the Flipflops? Charge injection when tristating tristate buffers? Neither of which are included in your models. Bruce Bob Stewart wrote: Fellow Timenuts: I'm trying to square reality with the modeling that I did, and nothing makes sense. When I modeled the result of just my 2.4K resistor with the caps and resistor the PIC datasheet says it has in it, there's no relationship. The model says I'll get millivolts out. Here's how I calculate what I'm actually getting: ADC VRef is 2.5V 10-bit ADC = 1024 positions Max ADC from TIC = 975 975/1024*2.5 = 2.38V Max TIC value Min ADC from TIC = 293 293/1024*2.5 = 0.715V Min TIC value A range of 0.715V-2.38V is totally outside my expectations. The only way I can get close to these values is if the internal CHOLD in the PIC is only a fraction of the 120pf they say it has - say 20pf. Any thoughts would be appreciated. Bob - AE6RV ___ 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] HP 10811 - 60165 Info Request
The single oven HP10811's heater supply is spec 20 to 30V, (=18V is mostly OK, 19V is better) The Inner oven voltage spec on the Dual Oven 10811s that I have is 12 to 30Volts, (All work good down to ~11V) Internally my dual oven units use a 5V ref in their heater controller instead of a 10V reference. The thermistor bridge is 5V on both) The outer oven needs ~5V nom to operate at ~115 deg F. 10 Volt max from an outer oven linear controller works good for Lab work. For best TC, the Dual oven units that I've tested really need an outer oven controller. On a couple of units, the temp TC went from around 1e-10 / deg C without the outer oven to 1e-12 /degC. Outer oven Pin outs; 1-GREY thermistor#1 (100K ohm@ 25C) 2-GREY thermistor lead#2 3-RED Heater#1 (~12 Ohm) 4-RED Heater lead#2 5- NC 6- NC *** 1 - BRN Oscillator Return (Com) 2 - RED Oscillator Power (+12V) 3 - ORG Oven Monitor Return (Com) 4 - YEL Oven Monitor Output 5 - GRN Oven Power (+18-24V) 6 - BLU Oven Return (Com) Thomas Knox ** To: time-nuts at febo.com From: johncroos at aol.com Date: Mon, 10 Mar 2014 14:17:58 -0400 Subject: [time-nuts] HP 10811 - 60165 Info Request I have acquired one of these double oven oscillators. Seems like a useful thing. Need info on pin outs, and operating voltages. Also any other useful information or links to same would be appreciated. Please reply off list with any files of specs etc to my email - johncroos at aol.com All help appreciated. Best regards to all john c roos k6iql ___ ___ 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] Modeling vs reality question re my TIC
Wouldn't those types of problems tend to make the result worse in some obvious way, instead of better than expected? I'm getting an ADC swing from about .7V to about 2.4V; which corresponds to the usual diode sink at .7V and probably just blind luck with the 2.4V max being so close to the 2.5V VRef. In the plot below, I zapped the DAC on my system to get a picture of the charge ramp. The red dots are the TIC with the 10ns uncorrected jitter from a nav receiver. The purple is a 30 second rolling average. Am I right in thinking this is a typical RC charge ramp? Not trying to be argumentative, I'm just trying hard to understand. http://www.evoria.net/AE6RV/TIC/ChargeRamp.png Bob From: Bruce Griffiths bruce.griffi...@xtra.co.nz To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 10, 2014 3:53 PM Subject: Re: [time-nuts] Modeling vs reality question re my TIC Metastability in the Flipflops? Charge injection when tristating tristate buffers? Neither of which are included in your models. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Modeling vs reality question re my TIC
Charge injection could well account for the offset from the expected minimum. There are no forward biased diodes in your circuit. It would be helpful to capture the 125 buffer input signal waveforms (and if possible the timing capacitor waveform) rather than trying to infer whats going on from the ADC plots. Bruce Bob Stewart wrote: Wouldn't those types of problems tend to make the result worse in some obvious way, instead of better than expected? I'm getting an ADC swing from about .7V to about 2.4V; which corresponds to the usual diode sink at .7V and probably just blind luck with the 2.4V max being so close to the 2.5V VRef. In the plot below, I zapped the DAC on my system to get a picture of the charge ramp. The red dots are the TIC with the 10ns uncorrected jitter from a nav receiver. The purple is a 30 second rolling average. Am I right in thinking this is a typical RC charge ramp? Not trying to be argumentative, I'm just trying hard to understand. http://www.evoria.net/AE6RV/TIC/ChargeRamp.png Bob From: Bruce Griffithsbruce.griffi...@xtra.co.nz To: Bob Stewartb...@evoria.net; Discussion of precise time and frequency measurementtime-nuts@febo.com Sent: Monday, March 10, 2014 3:53 PM Subject: Re: [time-nuts] Modeling vs reality question re my TIC Metastability in the Flipflops? Charge injection when tristating tristate buffers? Neither of which are included in your models. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Modeling vs reality question re my TIC
Unfortunately, I don't have a DSO, and I don't see any way to capture waveforms with the equipment I have available to me. And then there's the insurmountable problem of not having access to the 120pf cap in the PIC. I may have to just accept it without understanding it. At least success is a good problem to have and not a bad one. I'm sending a board to a friend soon, and if the results repeat for him, it's not just a fluke. Bob From: Bruce Griffiths bruce.griffi...@xtra.co.nz To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 10, 2014 5:32 PM Subject: Re: [time-nuts] Modeling vs reality question re my TIC Charge injection could well account for the offset from the expected minimum. There are no forward biased diodes in your circuit. It would be helpful to capture the 125 buffer input signal waveforms (and if possible the timing capacitor waveform) rather than trying to infer whats going on from the ADC plots. 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.
