TB 9-6625-1098-24
(12) Compare readings recorded in (8) and (11) above. If difference exceeds value
recorded in (8) above by more than 1.5 dB, perform b below.
(13) S e t M E T E R R A N G E s w i t c h t o 1 0 0 % ( S E T L E V E L ) a n d M O D E s w i t c h
t o MANUAL.
(14) Repeat technique of (2) through (13) above for TI frequency dial settings and
indications listed in table 7. If difference between MANUAL and AUTOMATIC null
exceeds limits specified, perform b below.
Table 7. Automatic Null
Difference between
Test
MANUAL null
instrument
Calibrator
and
frequencies
AUTOMATIC null
(kHz)
RANGE
dial
(dB)
switch settings
settings
50
X1K
50
+1.5
100
X10K
10
+1.5
250
X10K
25
+1.5
600
X10K
60
+1.5
.035
X1
35
+3.0
.400
X10
40
+1.5
b. Adjustments
(1) Repeat a (2) through (7) above.
(2) Set MODE selector switch to AUTOMATIC.
(3) Set METER RANGE switch to .0003 VOLTS.
(4) Rotate A3R30 (fig. 1) ccw and then cw for best null indication on TI meter.
Record TI meter indication.
NOTE
When adjusting A3R30, turn control a small increment and
allow TI meter indication to stabilize before obtaining TI
indication.
(5) Adjust A3R30 cw for 1 minor division (on TI meter 0 to 1 scale) above indication
recorded in (4) above (R).
(6) Repeat 16 a (1) through (14) above.
17. Fundamental Frequency Rejection
a. Performance Check
(1) Connect equipment as shown in figure 3.