gainsw=1
Measure Noise (noise signal amplitude) at radio board J3
≤
-55dBu
(-58)
Tap edge of radio board repeatedly at corner opposite from power connections
with ceramic screwdriver handle and measure noise at demodulated carrier at
radio board J3 referenced to step #40.100.10 value
0 to 18dB(r)
(+5)
Using the test panel key pad navigate to the Gain screen and change audio gain to "Gain 45"
level=45 (changes audio level to 45)
Measure Noise at radio board J3
≤
-53dBu
(-57)
Using the test panel key pad navigate to the "Gainsw" screen
select "auto"
gainsw=0
Mic gain pot taper test
Prerequisite(s) Unit in set-up mode
Note
Entering Set-up mode is not necessary if the Alternate Method is exercised.
DUT in "Passthru"
FREQ set to highest frequency
Audio Gain set to "Gain 45"
Gainsw set to "auto"
-55 dBu, 250Hz, low distortion, sinusoidal signal in at audio input rig
Note
Neither audio board LED (D5 nor D6) are red (limiter not activated)
Note
It is vital that the demodulation device (typically an FM modulation meter/analyzer) not be permitted to auto range
while performing the remainder of test step #40.110
Measure audio signal level at demodulated carrier at radio board J3
0dB reference
(0)
Note
#40.110.20.10 carrier signal deviation varies a bit with different batches of digital pot IC's at the maximum gain
setting
Change audio Gain setting to "Gain 22"
level=22 (changes audio level to 22)
Measure audio signal level at demodulated carrier at radio board J3
-24 to -22dB(r)
(-23)
Change audio Gain setting to "Gain 22"
