TB 9-6625-170-24
S1
S2
R1
100?
1
R2
4
TI
2
100?
Calibrator
9
1
S3
11
2
Figure 6. CMR Dc Unbalance Test Setup.
= 20 log
∗
(8) Using the larger voltage of steps (6 )and (7), compute the common mode rejection
.
(CMR) (in db) as follows:
(9) CMR will be ≥ 140 db.
b. Adjustments. None.
15. CMR AC Balance
a. Performance Check
(1) Connect TI as shown in figure 7.
Figure 7. CMR AC Balance Test Setup.
(2) Adjust the function generator for a 20 V pp sine wave at 60 Hz.
(3) Set S1 to 2.
(4) Note the peak-to-peak signal display on the oscilloscope as e.
= 20 log
∗
(5) Compute
the
common
mode
rejection
(CMR)
(in
db)
as
follows:
.