Calibrator
SC200 Calibration
63
Edge Amplitude Calibration
To do an Edge Amplitude calibration:
1. Push the OPTIONS and NEXT SECTION softkeys until the display shows
Set up to measure fast edge amplitude.
2. Use the BNC cable and BNC to double-banana adapter to connect the scope
out connector of the Product to the HP 3458A as shown in Figure 18.
3. Set the HP 3485A to DCV, NPLC = .01, LEVEL 1, TRIG LEVEL, and the
DELAY to 0.0002 to measure the top part (topline) of the waveform. Set the
DELAY to 0.0007 to measure the lower part (baseline) of the waveform. Set
the meter range to a range that shows the maximum resolution for the topline
measurements. Use this same range for the related baseline measurements
at each step.
Note
The topline is near 0 V, and the baseline is a negative voltage in the
EDGE function.
4. At each calibration step, read measurements for a minimum of two seconds,
with the HP 3458A MATH function to get the average or mean value.
The “true amplitude” of the waveform is the difference between the topline
and baseline measurements, with a correction for the load resistance error.
To make this correction, multiply the measurements by (0.5 * (50 +
Rload)/Rload), where Rload = actual feedthrough termination resistance.
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