RED PT500-2, Service Manual

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PT500-2 Service Manual
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Figure 5.3 Schematic Diagram for IF System
Receiving Audio Signal Processing:
The audio processing circuit of receiver consists of IC300 and the peripheral circuit. Voice
signals from IC200 are sent to IC301
（
CTCSS signaling filter circuit
）
and IC300-D
respectively after amplified in IC300-C. After that, the signals are removed of the HF and LF
components after amplification, de-emphasis and filtering by other units of IC300, and only
audit components from 300 to 3000Hz can be sent to audio power amplifier (IC302) after
amplified in Q300 and adjusted by volume potentiometers.
Figure 5.4 Schematic Diagram for Audio Processing of Receiver