TB 9-6695-263-35
(15) Press AM pushbutton and adjust A18R19 (fig. 1) for a minimum display less
than 0.2 percent.
NOTE
The specification for incidental AM requires 0.5 times residual
AM be subtracted. Residual AM, requires 0.5 times residual
AM be subtracted.
Residual AM can be measured by
momentarily disconnecting audio - input to calibration fixture
and noting displayed AM; - Subtracting 0.5 times displayed AM
from AM measured in (15) above gives actual incidental AM.
a. Performance Check
(1) Connect equipment as shown in figure 2, except connect calibration fixture FM
32 OUTPUT to TI INPUT.
(2) Set TI controls as listed in (a) through (c) below:
(a) Press 3.1 SPCL and MEASUREMENT FM pushbuttons.
(b) Press RATIO % pushbutton to off.
(c) Press PEAK + pushbutton to on.
(3) Adjust calibrator wideband frequency to 1 kHz and output level for a 5 kHz peak
deviation as displayed on TI.
(4) Press MEASUREMENT AM pushbutton.
(5) Momentarily disconnect cable from calibration fixture audio input and record
residual AM displayed on TI.
(6) Reconnect cable to calibration fixture and record AM displayed on TI.
(7) Subtract one-half of value recorded in (5) above from value recorded in (6) above.
Result will be 0.2 percent or less.
(8) Position controls as listed in (a) through (c) below:
(a) MEASUREMENT FM pushbutton pressed.
(b) All HP FILTER pushbuttons pressed to off.
(c) LP FILTER >20 kHz pushbutton pressed.
(9) Adjust calibrator frequency to 1 kHz and output level for 10 kHz peak deviation
times calibration factor value recorded in paragraph 15 a (2).
(10) Adjust calibrator frequency to 20 Hz and 10 kHz. TI will indicate FM between
9.79 and 10.21 kHz at each frequency.
(11) Adjust calibrator frequency to 10 kHz and output level to 10 kHz peak deviation.
(12) Measure distortion on audio analyzer with 30 kHz low-pass and 400 Hz high-
pass filtering. If measured distortion does not indicate 0.1 percent or less, perform b below.
b. Adjustments
(1) Disconnect cable from TI INPUT.
