Today I attempted to do some Quad measurements (fresh out of the box sys 1.31, app 2.30. fpga?? (I wanted a base-line before I changed anything)) but I ran into a couple of snags:
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All my waveform displays appear to be 1/10 of the sine wave input signal. Where do you set the 1x or 10x probe type? I can’t find a menu choice for that in the Quad Manual 0.91b. Is there a 10x probe selection option?
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The Auto trigger mode is very flaky. It has trouble finding sync and many times displays garbage when it appears to be synched, but after a few seconds it may lock in and display properly. If it doesn’t lock in properly, then you must move the trigger level out of the signal and then bring it back and try again. Success rate appears to be about 30%
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The Normal mode trigger on the other hand appears to lock properly and always displays an appropriate waveform.
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The Quad-measured Vpp does seem to track the Quad displayed waveform amplitude properly, but the Quad-measured Vpp appears to be off by a factor of 20, 1/20th of the actual input signal; or to put another way, 1/2 of the 1/10 amplitude observed waveform.
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All amplitude and frequency measurements of the input signal are conducted off a TEE’d BNC cable to a Tektronix TDS-210 60Mhz scope with 1GS/s sample rate. The input to the Quad uses an MCX to BNC adapter and BNC cable from the TEE that also feeds the Tektronix scope.
Once I get this 1/10 issue resolved, then I will conduct accurate bandwidth measurements at 1Mhz increments. My initial findings using only the display results shows the roll-off (-3db)to start between 3 and 4 Mhz and at 10Mhz the amplitude falls to 40% of 1/10th of the input signal. Once again, all these measurements were conducted with sine wave signals.