User's Manual

Adjustments
52
P6330 3.5 GHz Differential Probe Instruction Manua l
12. Calculate the common-mode gain (A
CM
) as follows:
(V
out
1--V
out
2) ÷ (V
in
1--V
in
2).
13. Calculate the CMRR as follows: 20 log (0.2/|A
CM
|)
14. Reverify that the offset is 0 V, ±3.0 mV (repeat steps 1
through 3). If the offset voltage magnitude is greater t han 3. 0 mV,
or if the CMRR is less than 60 dB, disconnect the probe from the
test circuit. Repeat the procedure, beginning with step 1 on
page 50, to compensate for the adjustment interaction.