Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Physikfan, Sun Feb 26 2017, 04:25PMI would like to introduce a Tektronix 11801 Sampling Oscilloscope:
Square wave with 10 μs period (100 kHz) from the calibration socket:
Rise time of this square wave, about 300 ps:
Measurements on a 3 GHz square wave will follow.
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Sulaiman, Sun Feb 26 2017, 06:52PM
Rise time is normally taken between 10% and 90%
so IF your 'scope display is 100 ns/div.
then your rise time is more like 200 ns.
NICE 'SCOPE :)
Sulaiman, Sun Feb 26 2017, 06:52PM
Rise time is normally taken between 10% and 90%
so IF your 'scope display is 100 ns/div.
then your rise time is more like 200 ns.
NICE 'SCOPE :)
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Physikfan, Sun Feb 26 2017, 08:08PM
Hi Sulaiman
"Rise time is normally taken between 10% and 90%", correct.
At the horizontal axis there are 200 ps/division.
According to the Tek manual the rise time of the calibrator output should be 250 ps.
Physikfan, Sun Feb 26 2017, 08:08PM
Hi Sulaiman
"Rise time is normally taken between 10% and 90%", correct.
At the horizontal axis there are 200 ps/division.
According to the Tek manual the rise time of the calibrator output should be 250 ps.
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
DerAlbi, Mon Feb 27 2017, 07:13PM
Not sure what the point of the whole post is, but if its about the too long rise time, keep in mind that the 3GHz bandwidth also limits the rise time to ~120ps. Combined with a 250ps output rise time the result seems ok. The calibration output has no need to be faster since it must only provide a square wave good enough for calibration. The point of calibration is not to get the best rise time, but to get the correct input compensation.
DerAlbi, Mon Feb 27 2017, 07:13PM
Not sure what the point of the whole post is, but if its about the too long rise time, keep in mind that the 3GHz bandwidth also limits the rise time to ~120ps. Combined with a 250ps output rise time the result seems ok. The calibration output has no need to be faster since it must only provide a square wave good enough for calibration. The point of calibration is not to get the best rise time, but to get the correct input compensation.
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
..., Mon Feb 27 2017, 09:06PM
It is not a 3GHz scope, it is a 50GHz scope. Depending on what sampling head is installed (I can't make out the part number from the picture) the usable bandwidth will be lower, most likely 20GHz. The calibration output is specified as 'approximately 250ps' (seriously, no more information given) so his measurements are accurate. Finding a fast enough signal to accurately measures the scopes internal rise time can be tricky, a step recovery diode could work or some ECL logic can have rise times on the order of 50ps but unless you have a very slow sample head that is not very useful.
..., Mon Feb 27 2017, 09:06PM
It is not a 3GHz scope, it is a 50GHz scope. Depending on what sampling head is installed (I can't make out the part number from the picture) the usable bandwidth will be lower, most likely 20GHz. The calibration output is specified as 'approximately 250ps' (seriously, no more information given) so his measurements are accurate. Finding a fast enough signal to accurately measures the scopes internal rise time can be tricky, a step recovery diode could work or some ECL logic can have rise times on the order of 50ps but unless you have a very slow sample head that is not very useful.
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
DerAlbi, Tue Feb 28 2017, 12:32AM
Sry i misread, i thought there was a problem
DerAlbi, Tue Feb 28 2017, 12:32AM
Sry i misread, i thought there was a problem
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Physikfan, Wed Mar 01 2017, 05:07AM
The sampling head SD 22 used has a bandwidth of
12.5 GHz, dual channel,
the rise time is at 28ps,
for low-noise sampling measurements:
Physikfan, Wed Mar 01 2017, 05:07AM
The sampling head SD 22 used has a bandwidth of
12.5 GHz, dual channel,
the rise time is at 28ps,
for low-noise sampling measurements:
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Physikfan, Wed Sept 13 2017, 07:39AM
I have a Tektronix 11801 sampling oscilloscope, which does not start after switching on because of problems with built in batteries.
Please, are there experiences with such problems within this forum?
Physikfan, Wed Sept 13 2017, 07:39AM
I have a Tektronix 11801 sampling oscilloscope, which does not start after switching on because of problems with built in batteries.
Please, are there experiences with such problems within this forum?
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
Plasma, Wed Sept 13 2017, 08:38AM
Hi, good luck finding electronic to process a 50ghz signal in real time, 6ghz maybe, but it samples it then process it.
Plasma, Wed Sept 13 2017, 08:38AM
Hi, good luck finding electronic to process a 50ghz signal in real time, 6ghz maybe, but it samples it then process it.
Re: Sampling Oscilloscope Tektronix 11801, 12.5 GHz, 28ps rise time
klugesmith, Wed Sept 13 2017, 11:11AM
Good stuff there.
The speed of sampling head technology certainly does not follow Moore's law, or the progression of clock rates in microprocessors.
Before the 11801 and its pod bays, there was the 7000 series. Computer-free CRT display.
Sampling head plug-ins included the S-4: Analog bandwidth 14.5 GHz. Risetime 25 ps. Introduced in 1968.
Trouble is, if one gets damaged by ESD through carelessness, you can't get the parts to fix it.
The 7000-series head with TDR step generator & sampler was a bit slower -- 35 ps Tr if I recall correctly. Handy for me to measure printed-circuit transmission lines in the early 1980's. Or to teach TDR fundamentals, and show how pinching a coaxial cable with your fingers could make a permanent indentation in the characteristic impedance at that spot.
klugesmith, Wed Sept 13 2017, 11:11AM
Good stuff there.
The speed of sampling head technology certainly does not follow Moore's law, or the progression of clock rates in microprocessors.
Before the 11801 and its pod bays, there was the 7000 series. Computer-free CRT display.
Sampling head plug-ins included the S-4: Analog bandwidth 14.5 GHz. Risetime 25 ps. Introduced in 1968.
Trouble is, if one gets damaged by ESD through carelessness, you can't get the parts to fix it.
The 7000-series head with TDR step generator & sampler was a bit slower -- 35 ps Tr if I recall correctly. Handy for me to measure printed-circuit transmission lines in the early 1980's. Or to teach TDR fundamentals, and show how pinching a coaxial cable with your fingers could make a permanent indentation in the characteristic impedance at that spot.
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