User Manual

Adjustment Proc
edures
AC CMRR
1. Change the function generator to sine wave.
2. Set the frequency of the function generator to 1 MHz and the output amplitude to approximately 4 V pk-pk, (2 V peak).
3. Set the probe to ÷ 5 attenuation, 5 MHz bandwidth, DC reject off.
4. Change the scope horizontal setting to 100 ns/div. If necessa ry, adjust the channel 2 volts/div and trigger level for a
stable trigger.
5. The displayed sine wave is the common mode feedthrough. If the probe is severely misadjusted, the w aveform may
be off screen.
6. Adjust the ÷ 5 AC CMRR adjustment for minimum amplitude. Usually it is not possible to completely eliminate the
high frequency feedthrough.
7. Change the probe to ÷ 50 attenuation.
8. Set the output amplitude of the function generator to approximately 10 V pk-pk (5 V pk).
9. Adjust the ÷ 50 AC CMRR adjustment for minimum amplitude.
10. There is some interaction between the DC and AC CMRR adjustments. Repeat the DC CMRR adjustment steps 3 to 10.
11. Remove all connections from the probe. Carefully replace the top cover of the control box and the four retaining screws.
This completes the adjustment procedures.
48 P6250 & P6251 Technical Reference