3.2 FM : AdjustT3
(SENSITIVITY AND S/N) to
let the SINAD be the best
.
.
3.3 AM/FM
:
Adjust
VR1
(AUDIO OUTPUT)
to let the audio output for
FM
0.1~0.32V and AM 0.12~0.16V
3.4
Adjust
VR20
(SQ)
, when INPUT is 62dBuV and OUTPUT would be 3.8V.
Testing Point is at TP1.
2.WX Tuning
Description: WX is just a 1050Hz signal warning system.
A. Frequency reference point is as TP5. It should be 10.25MHz
±
60Hz.
B. The voltage at TP6 should be 1.5 to 1.75V. If not, tune L6 till get the desired value
C. Set the testing point at the output of TP4, tune T4 till getting maximum sensitivity
and minimum distortion.
D. Set the testing point at TP10 for 1050Hz signal testing. Usually, voltage at TP10
should be high (4.9V). Upon receipt 1050Hz signal, the voltage should be low (0V).
The above testing is following ETS300-135 standard for FM, EIA/TIA-382-A for AM
including ( FCC/CE and client requirement)
PREPARED BY :
Mr. YK Liu
APPROVED BY :
Date: 6-Apr-05
