Since I was working at Tektronix at the time, I still remember the first instruments that were in the family. Like the main frames 11801, 11802, CSA801, CSA802, CSA803, etc and sampling heads SD-20, SD-22, SD-24, etc. You can try a google search like "Tektronix 11801 filetype:pdf". You can also try a google search like "Tektronix SD-24 filetype:pdf". If you want to know more about google filetypes, enter "google filetype search" into a google search. To find out more about sampling heads you can look for information on the instruments they connect to. w140.com has a lot of information on both the mainframes and the sampling heads. http://w140.com/tekwiki/wiki/Main_Page#11000_Series http://w140.com/tekwiki/wiki/SD-24 It is good to know more google-fu. It is even better to be able to still remember about any of this. :) Ivan Cousins

I still work for Tektronix, but not in Service or the sampling scope product line. I'm a Tektronix field RF Application Engineer. You can find the service manual for the SD-24 at: http://www.tek.com/oscilloscope/sd24-manual/sd-24-service-manual But it's not user repairable, so there are no schematics (just block diagrams). The SD-24 was introduced about 25 years ago for the 11801/11802 family of sampling scopes. The SD-24 is a dual TDR sampling head, so it can generate a fast risetime step from either or both outputs. The steps can be the same polarity (for common mode testing) or opposite polarity (for differential mode testing). The sampling bridges measure both the incident (forward) and reflected pulses. The SD-26 is basically the same product without the TDR pulse sources. The SD-22 is a lower noise (and lower bandwidth) version of the SD-26. As pointed out by others, these heads aren't useful without a 11800 or CSA800 family mainframe. The SD-series measure signals using sequential equivalent-time sampling. * Single events can't be measured. Only repeating signals with a low-jitter trigger source can be measured. The trigger must be an externally input signal (unless you use the SD-24 with the internal TDR step source or an external signal pickoff transformer). * Each trigger edge which is accepted by the mainframe is delayed by a precise amount and then used to create a sampling strobe which is sent by the mainframe to the sampling head. * The sampling head (SD-24/26/22) actually measures the error difference between an internal feedback loop and the sampled input voltage. Since the sampling bridge has a high loss, the error voltage is multiplied by the assumed bridge loss to create the new feedback loop voltage. A high resolution low-noise A/D converter measures the loop voltage for the microprocessor-created raster scan display on the CRT. * The sampling system takes around 10 microseconds to reset between triggers. So no more than about 100K triggers and samples can be made per second. It might be a little slower than this - I'm remembering this from my experience over 20 years ago. * The delay from the trigger input to the sampling strobe (sent to the SD-xx sampling head) is sequentially delayed by slightly increasing time delays to create a time domain display. The delay increment between samples can be less than 1 ps (down in the 100 fs range). * Since the signal is not actually sampled in real time, this is called equivalent-time sampling. In this case, the sampling strobe is sequentially advanced in time upon trigger signal acceptance. This results in very high time accuracy with low jitter (a couple of ps RMS jitter in these older products). * The voltage measurement range is usually a few hundred millivolts peak-peak, while the damage level is at around 3 volts. -- Bill Byrom N5BB On Fri, Apr 24, 2015, at 10:42 PM, Ivan Cousins wrote: > Since I was working at Tektronix at the time, I still remember the > first instruments that were in the family. > > Like the main frames 11801, 11802, CSA801, CSA802, CSA803, etc and > sampling heads SD-20, SD-22, SD-24, etc. > > You can try a google search like "Tektronix 11801 filetype:pdf". You > can also try a google search like "Tektronix SD-24 filetype:pdf". > > If you want to know more about google filetypes, enter "google > filetype search" into a google search. > > To find out more about sampling heads you can look for information on > the instruments they connect to. > > w140.com has a lot of information on both the mainframes and the > sampling heads. > > http://w140.com/tekwiki/wiki/Main_Page#11000_Series > http://w140.com/tekwiki/wiki/SD-24 > > It is good to know more google-fu. It is even better to be able to > still remember about any of this. :) > > Ivan Cousins > _________________________________________________ > 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.

Thanks all for your info about these modules. Daniel On 26/04/2015 01:26, Bill Byrom wrote: > I still work for Tektronix, but not in Service or the sampling scope > product line. I'm a Tektronix field RF Application Engineer. > > You can find the service manual for the SD-24 at: > http://www.tek.com/oscilloscope/sd24-manual/sd-24-service-manual But > it's not user repairable, so there are no schematics (just block > diagrams). > > The SD-24 was introduced about 25 years ago for the 11801/11802 family > of sampling scopes. The SD-24 is a dual TDR sampling head, so it can > generate a fast risetime step from either or both outputs. The steps can > be the same polarity (for common mode testing) or opposite polarity (for > differential mode testing). The sampling bridges measure both the > incident (forward) and reflected pulses. > > The SD-26 is basically the same product without the TDR pulse sources. > > The SD-22 is a lower noise (and lower bandwidth) version of the SD-26. > > As pointed out by others, these heads aren't useful without a 11800 or > CSA800 family mainframe. The SD-series measure signals using sequential > equivalent-time sampling. > * Single events can't be measured. Only repeating signals with a > low-jitter trigger source can be measured. The trigger must be an > externally input signal (unless you use the SD-24 with the internal > TDR step source or an external signal pickoff transformer). > * Each trigger edge which is accepted by the mainframe is delayed by a > precise amount and then used to create a sampling strobe which is > sent by the mainframe to the sampling head. > * The sampling head (SD-24/26/22) actually measures the error > difference between an internal feedback loop and the sampled input > voltage. Since the sampling bridge has a high loss, the error > voltage is multiplied by the assumed bridge loss to create the new > feedback loop voltage. A high resolution low-noise A/D converter > measures the loop voltage for the microprocessor-created raster scan > display on the CRT. > * The sampling system takes around 10 microseconds to reset between > triggers. So no more than about 100K triggers and samples can be made > per second. It might be a little slower than this - I'm remembering > this from my experience over 20 years ago. > * The delay from the trigger input to the sampling strobe (sent to the > SD-xx sampling head) is sequentially delayed by slightly increasing > time delays to create a time domain display. The delay increment > between samples can be less than 1 ps (down in the 100 fs range). > * Since the signal is not actually sampled in real time, this is called > equivalent-time sampling. In this case, the sampling strobe is > sequentially advanced in time upon trigger signal acceptance. This > results in very high time accuracy with low jitter (a couple of ps > RMS jitter in these older products). > * The voltage measurement range is usually a few hundred millivolts > peak-peak, while the damage level is at around 3 volts. > > -- > Bill Byrom N5BB > > > > On Fri, Apr 24, 2015, at 10:42 PM, Ivan Cousins wrote: >> Since I was working at Tektronix at the time, I still remember the >> first instruments that were in the family. >> >> Like the main frames 11801, 11802, CSA801, CSA802, CSA803, etc and >> sampling heads SD-20, SD-22, SD-24, etc. >> >> You can try a google search like "Tektronix 11801 filetype:pdf". You >> can also try a google search like "Tektronix SD-24 filetype:pdf". >> >> If you want to know more about google filetypes, enter "google >> filetype search" into a google search. >> >> To find out more about sampling heads you can look for information on >> the instruments they connect to. >> >> w140.com has a lot of information on both the mainframes and the >> sampling heads. >> >> http://w140.com/tekwiki/wiki/Main_Page#11000_Series >> http://w140.com/tekwiki/wiki/SD-24 >> >> It is good to know more google-fu. It is even better to be able to >> still remember about any of this. :) >> >> Ivan Cousins >> _________________________________________________ >> 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.

Bill, As I recall it, it has a 400 kS/s rate. Undersampling as it is, if properly used, it is a marvelous tool. The TDR capability had such a live component to it that I miss in newer (but butter calibrated) systems. No wonder I have a system myself these days. The one thing I would love to have, is to be able to run the TDR/TDT post-processing software. I haven't seen any free alternative either. Cheers, Magnus On 04/26/2015 06:26 AM, Bill Byrom wrote: > I still work for Tektronix, but not in Service or the sampling scope > product line. I'm a Tektronix field RF Application Engineer. > > You can find the service manual for the SD-24 at: > http://www.tek.com/oscilloscope/sd24-manual/sd-24-service-manual But > it's not user repairable, so there are no schematics (just block > diagrams). > > The SD-24 was introduced about 25 years ago for the 11801/11802 family > of sampling scopes. The SD-24 is a dual TDR sampling head, so it can > generate a fast risetime step from either or both outputs. The steps can > be the same polarity (for common mode testing) or opposite polarity (for > differential mode testing). The sampling bridges measure both the > incident (forward) and reflected pulses. > > The SD-26 is basically the same product without the TDR pulse sources. > > The SD-22 is a lower noise (and lower bandwidth) version of the SD-26. > > As pointed out by others, these heads aren't useful without a 11800 or > CSA800 family mainframe. The SD-series measure signals using sequential > equivalent-time sampling. > * Single events can't be measured. Only repeating signals with a > low-jitter trigger source can be measured. The trigger must be an > externally input signal (unless you use the SD-24 with the internal > TDR step source or an external signal pickoff transformer). > * Each trigger edge which is accepted by the mainframe is delayed by a > precise amount and then used to create a sampling strobe which is > sent by the mainframe to the sampling head. > * The sampling head (SD-24/26/22) actually measures the error > difference between an internal feedback loop and the sampled input > voltage. Since the sampling bridge has a high loss, the error > voltage is multiplied by the assumed bridge loss to create the new > feedback loop voltage. A high resolution low-noise A/D converter > measures the loop voltage for the microprocessor-created raster scan > display on the CRT. > * The sampling system takes around 10 microseconds to reset between > triggers. So no more than about 100K triggers and samples can be made > per second. It might be a little slower than this - I'm remembering > this from my experience over 20 years ago. > * The delay from the trigger input to the sampling strobe (sent to the > SD-xx sampling head) is sequentially delayed by slightly increasing > time delays to create a time domain display. The delay increment > between samples can be less than 1 ps (down in the 100 fs range). > * Since the signal is not actually sampled in real time, this is called > equivalent-time sampling. In this case, the sampling strobe is > sequentially advanced in time upon trigger signal acceptance. This > results in very high time accuracy with low jitter (a couple of ps > RMS jitter in these older products). > * The voltage measurement range is usually a few hundred millivolts > peak-peak, while the damage level is at around 3 volts. > > -- > Bill Byrom N5BB > > > > On Fri, Apr 24, 2015, at 10:42 PM, Ivan Cousins wrote: >> Since I was working at Tektronix at the time, I still remember the >> first instruments that were in the family. >> >> Like the main frames 11801, 11802, CSA801, CSA802, CSA803, etc and >> sampling heads SD-20, SD-22, SD-24, etc. >> >> You can try a google search like "Tektronix 11801 filetype:pdf". You >> can also try a google search like "Tektronix SD-24 filetype:pdf". >> >> If you want to know more about google filetypes, enter "google >> filetype search" into a google search. >> >> To find out more about sampling heads you can look for information on >> the instruments they connect to. >> >> w140.com has a lot of information on both the mainframes and the >> sampling heads. >> >> http://w140.com/tekwiki/wiki/Main_Page#11000_Series >> http://w140.com/tekwiki/wiki/SD-24 >> >> It is good to know more google-fu. It is even better to be able to >> still remember about any of this. :) >> >> Ivan Cousins >> _________________________________________________ >> 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. >

Yes, that's about right, Magnus. I believe it depends on how many sampling channels are in use, since there is a factor of two interleaving in some cases (to the best of my memory). That is really the holdoff rate between the acceptance of trigger edges. If the trigger signal rate is lower (such as 10 kHz), that will be the sampling rate. If the trigger signal is at a higher frequency (such as 400 MHz), only one out of every 1,000 trigger edges might be accepted. Each accepted trigger event causes a single sample of the input voltage (relative to the feedback voltage) to be taken. The sampled voltage is significantly attenuated due to sampler loss, so the sampler output is multiplied by the assumed correction factor to change the feedback voltage (which is then measured by a low speed high resolution A/D). If the gain is set correctly, the step response is pretty good, but due to nonlinearity there is a small digital feedback error resulting in slight ringing at the sampling rate. This ringing is often not noticed unless the scope time/div is set to a low value. Sampling oscilloscopes are only undersampled with respect to signals which are not harmonically related to the trigger signal. The sequential equivalent time sampling rate is often several THz/sec. Basic TDR/TDT doesn't need any additional software to get an estimate of the reflected impedance. But the iConnect software (which was developed by a small company which Tektronix purchased many years ago) allows much higher accuracy and removes most of the ambiguity of multiple reflections. It also allows S-parameters to be extracted and SPICE models to be verified. This software isn't free - we have many more software engineers than hardware engineers these days! -- Bill Byrom N5BB On Sun, May 3, 2015, at 04:28 PM, Magnus Danielson wrote: > Bill, > > As I recall it, it has a 400 kS/s rate. > > Undersampling as it is, if properly used, it is a marvelous tool. > The TDR capability had such a live component to it that I miss in newer > (but butter calibrated) systems. > > No wonder I have a system myself these days. > > The one thing I would love to have, is to be able to run the TDR/TDT > post-processing software. I haven't seen any free alternative either. > > Cheers, > Magnus > > On 04/26/2015 06:26 AM, Bill Byrom wrote: > > I still work for Tektronix, but not in Service or the sampling scope > > product line. I'm a Tektronix field RF Application Engineer. > > > > You can find the service manual for the SD-24 at: > > http://www.tek.com/oscilloscope/sd24-manual/sd-24-service-manual But > > it's not user repairable, so there are no schematics (just block > > diagrams). > > > > The SD-24 was introduced about 25 years ago for the 11801/11802 family > > of sampling scopes. The SD-24 is a dual TDR sampling head, so it can > > generate a fast risetime step from either or both outputs. The steps can > > be the same polarity (for common mode testing) or opposite polarity (for > > differential mode testing). The sampling bridges measure both the > > incident (forward) and reflected pulses. > > > > The SD-26 is basically the same product without the TDR pulse sources. > > > > The SD-22 is a lower noise (and lower bandwidth) version of the SD-26. > > > > As pointed out by others, these heads aren't useful without a 11800 or > > CSA800 family mainframe. The SD-series measure signals using sequential > > equivalent-time sampling. > > * Single events can't be measured. Only repeating signals with a > > low-jitter trigger source can be measured. The trigger must be an > > externally input signal (unless you use the SD-24 with the internal > > TDR step source or an external signal pickoff transformer). > > * Each trigger edge which is accepted by the mainframe is delayed by a > > precise amount and then used to create a sampling strobe which is > > sent by the mainframe to the sampling head. > > * The sampling head (SD-24/26/22) actually measures the error > > difference between an internal feedback loop and the sampled input > > voltage. Since the sampling bridge has a high loss, the error > > voltage is multiplied by the assumed bridge loss to create the new > > feedback loop voltage. A high resolution low-noise A/D converter > > measures the loop voltage for the microprocessor-created raster scan > > display on the CRT. > > * The sampling system takes around 10 microseconds to reset between > > triggers. So no more than about 100K triggers and samples can be made > > per second. It might be a little slower than this - I'm remembering > > this from my experience over 20 years ago. > > * The delay from the trigger input to the sampling strobe (sent to the > > SD-xx sampling head) is sequentially delayed by slightly increasing > > time delays to create a time domain display. The delay increment > > between samples can be less than 1 ps (down in the 100 fs range). > > * Since the signal is not actually sampled in real time, this is called > > equivalent-time sampling. In this case, the sampling strobe is > > sequentially advanced in time upon trigger signal acceptance. This > > results in very high time accuracy with low jitter (a couple of ps > > RMS jitter in these older products). > > * The voltage measurement range is usually a few hundred millivolts > > peak-peak, while the damage level is at around 3 volts. > > > > -- > > Bill Byrom N5BB > > > > > > > > On Fri, Apr 24, 2015, at 10:42 PM, Ivan Cousins wrote: > >> Since I was working at Tektronix at the time, I still remember the > >> first instruments that were in the family. > >> > >> Like the main frames 11801, 11802, CSA801, CSA802, CSA803, etc and > >> sampling heads SD-20, SD-22, SD-24, etc. > >> > >> You can try a google search like "Tektronix 11801 filetype:pdf". You > >> can also try a google search like "Tektronix SD-24 filetype:pdf". > >> > >> If you want to know more about google filetypes, enter "google > >> filetype search" into a google search. > >> > >> To find out more about sampling heads you can look for information on > >> the instruments they connect to. > >> > >> w140.com has a lot of information on both the mainframes and the > >> sampling heads. > >> > >> http://w140.com/tekwiki/wiki/Main_Page#11000_Series > >> http://w140.com/tekwiki/wiki/SD-24 > >> > >> It is good to know more google-fu. It is even better to be able to > >> still remember about any of this. :) > >> > >> Ivan Cousins > >> _________________________________________________ > >> 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.

Hello, I've taken a first pass at using TimeLab over the weekend. I wasn't able to get it to work with my SRS sr 620 over RS232. I know that the com port / serial cable and counter are working. I can open terminal, talk to the counter, and make a measurement. When I setup a measurement in TimeLab If I hit the "monitor" button I don't see any activity. If I start the measurement, Time lab never gets past trying to establish communication with the counter. I'm sure its my fault. Any thoughs? thanks Lincoln

Lincoln, Did you configure the coulder to use RS232 rather than GPIB? It's in the manual. Cheers, Magnus On 05/04/2015 07:28 AM, lincoln wrote: > Hello, > I've taken a first pass at using TimeLab over the weekend. I wasn't able to get it to work with my SRS sr 620 over RS232. I know that the com port / serial cable and counter are working. I can open terminal, talk to the counter, and make a measurement. When I setup a measurement in TimeLab If I hit the "monitor" button I don't see any activity. If I start the measurement, Time lab never gets past trying to establish communication with the counter. I'm sure its my fault. > > Any thoughs? > > thanks > > Lincoln > _______________________________________________ > 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. >

Now I have to figure out how to use time lab. My TIE plots just show as a strait line, I can zoom in to show detail but the y scale will go form +1.00E0 to  +1.00E0 . I'm sure its a setting.

Hello Magnus, It was a baud rate issue. Time Monitor defaults to 9600 and Time Lab uses 19200. Changed the counter and time monitor to use 19.2k and every body is happy. Now I have to figure out how to use time lab. My TIE plots just show as a strait line, I can zoom in to show detail but the y scale will go form +1.00E0 to +1.00E0 . I'm sure its a setting. Thank you On May 4, 2015, at 10:40 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > Lincoln, > > Did you configure the coulder to use RS232 rather than GPIB? > It's in the manual. > > Cheers, > Magnus > > On 05/04/2015 07:28 AM, lincoln wrote: >> Hello, >> I've taken a first pass at using TimeLab over the weekend. I wasn't able to get it to work with my SRS sr 620 over RS232. I know that the com port / serial cable and counter are working. I can open terminal, talk to the counter, and make a measurement. When I setup a measurement in TimeLab If I hit the "monitor" button I don't see any activity. If I start the measurement, Time lab never gets past trying to establish communication with the counter. I'm sure its my fault. >> >> Any thoughs? >> >> thanks >> >> Lincoln >> _______________________________________________ >> 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.