However, that's unnecessary because you only need 2 channels to perform 2 differential measurements, using 2 differential probes (the probes do the summing already, no Math needed). Hi assuming that, you're considering using 4 channels to perform 2 negative and positive measurements, which you will then sum in a Math channel to give you the differential (which is why you ruled out a 2 channel device). System accuracy with sqrt of errors squared: sqrty (2 x (1%)^2 (probe) + 2 x (1.7%)^2 (DC accuracy)) = 2.7%ġ) Is this probe accuracy too conservative? Could we calibrate to increase accuracy? Perhaps we could just use a precision resistor since bandwidth is not very high and we can dial in full-scale usage as well? since we are doing a differential/math measurement I 2x these error sources below, although the other side should be ~0V. Error estimate for PS 4424 with 1:10 ProbesĪctual signal range: 150 (voltage max of signal) / 10 (1:10 probe)= 15VĮffective DC accuracy at 120V is 20V / 12V * 1% = 1.7% System accuracy with sqrt of errors squared: sqrt ((2%)^2 (probe) + (2.1%)^2 (DC accuracy)) = 2.9%ġ) silly question, can i turn off the bandwidth limit, specsheet says 100kHz and 1MHz, but not explicitly that it can be disabledĢ) what accuracy can i expect >10kHz, we do want to characterize rise time with good precision Error estimate for PS 4444 with PicoConnect 442 1000V ProbesĪctual signal range: 120 (voltage max of signal) / 25 (442 probe 1:25 attenuation)= 4.8VĮffective DC accuracy at 120V is 10V / 4.8 * 1% = 2.1% Background: we want to measure a differential signal (two actually hence we have eliminated PS 4262) from 0 ~ 150V and with a rise time of ~1us and 20 MS/s is desired, the instrument is battery powered but we may make a common reference via the charging port (hence we consider PS 4424).Ĭan you comment broadly on these figures and the PS 4444 specific questions?
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