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5.6.6 FM demod. gain and Squelch level adjustment
(1) Setting of measurement system
MT8802A
RF Input = “AUX”
FM Demod. out range=“40 kHz”, LPF=“off”, HPF=“off”
SG
RF Output Level=“0 dBm”
FM Mod. Freq.=“1 kHz”, Deviation=“40 kHz”
HP8903 Audio Analyzer
LPF=“30 kHz”
• Connect the RF output of SG to the MT8802A AUX Input terminal.
• Connect the MT8802A Demod. Output to the HP8903 AF input (100 k ohms)
terminal.
(2) Set the R223 (RSSI variable resistor) to the minimum position (full-counter-
clockwise) and adjust the R175 (Det variable resistor) so that the HP8903 mea-
surement result (AF level) is within 2.812 Vrms ±1%.
(3) Set the R223 (RSSI variable resistor) to the maximum position (full-clockwise).
(4) Setting of measurement system
SG
Change to the RF Output Level = –40 dBm.
Oscilloscope
Vert.=“0.5V/div”, Hor.=“0.2ms/div”
• Connect the MT8802A Demod. Output to the oscilloscope.
(5) Counterclockwise turn the R223 (RSSI variable resistor) until a 1 kHz waveform
appears on the oscilloscope screen. Be sure to turn the variable resistor from the
right to the left, taking into account the hysteresis.
5.6.7 Other variable resistors
Set the R32 (FM2 variable resistor), R7 (FSK1 variable resistor), and R11 (FSK2 vari-
able resistor) to the center position.
5.6 A16 AF
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