TB 9-6625-1999-35
(3) Adjust MOD ZERO SET R69 (fig. 1) for a 1.05 V indication on voltmeter (R).
(4) Set MODULATION SELECTOR switch to CW.
(5) Repeat (1) through (3) above until there is no voltage variation.
26. Modulation Meter Accuracy
a. Performance Check
(1) Connect measuring receiver to RF OUTPUT 50 Ω.
(2) Position controls as listed in (a) through (f) below:
(a) RANGE switch to 530KC-1800KC.
(c) ATTENUATOR switch to 1.0 VOLTS.
(d) MODULATION SELECTOR switch to INT. 1000∼.
(e) MODULATION AMPLITUDE control for a 50 percent modulation
indication on PERCENT MODULATION meter.
(f) ATTENUATOR VERNIER control for 1-V indication on R.M.S.
VOLTS meter.
(3) If measuring receiver does not indicate between 45 and 55 percent modulation,
perform b below.
(4) Adjust MODULATION AMPLITUDE control for 90 percent modulation
indication on MODULATION meter. If measuring receiver does not indicate between 85
and 95 percent, perform b below.
b. Adjustments
(1) Adjust MODULATION AMPLITUDE control for a 50-percent indication on
measuring receiver. Adjust MOD CAL R67 (fig. 1) for a 50 percent indication on
PERCENT MODULATION meter.
(2) Adjust ATTENUATOR VERNIER control for a 0.2 V indication on R.M.S.
VOLTS meter. If measuring receiver does not indicate between 45 and 55 percent
modulation, adjust A4R21 (fig. 3) for 50 percent modulation on measuring receiver (R).
(3) Repeat a above.
NOTE
above.
a. Performance Check
(1) Connect true rms voltmeter to RF OUTPUT 50 Ω.