Kenwood TH-77A Service Manual page 28

IA-/f/A/E
SEMICONDUCTOR DATA
FM Receiver Circuit MC3372D (TX-RX Units IC2 and IC202)
@Block Diagram
MC3372 GND
Squetch trigger
@Pin Functions
Description
A Colpitts oscillator circuit is set up by connecting a crystal oscillator. A signal is input to pin 1, and pin 2 is connected to Vcc
OSC Out when an external oscillator is used.
Mixer output
Power
Limiter amplifier input and decoupling (or output). Pins 6 and 7 are AC-grounded (or a feedback resistor and phase meter
capacitor are connected to pin 7).
DEC2 {LIM Out)
QUAD In Phase meter connection
AF Out An FM detected signal is output.
FAmp. Out Operational amplifier output
SQSW In Squelch switch input
Smeler Out A current corresponding to the limiter amplifier input signal level is output.
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SQSW Out Squelch switch output
GND Ground
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MIX In Mixer input
Note: The explanation in parentheses refers to FM receiver circuit MC3372.
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