RED PT500-2, Руководство по обслуживанию

Страница: 16 / 62

PT500-2 Service Manual
16
604PT50001002 AL cabinet asm.
1 2030PT500001X AL cabinet 1
2 2010CU600005X Radio top cover black 1
3 2020PT500001X Cabinet waterproof ring orange 1
4 2020PT500002X Power socket washer 1
5 301250607001X Machine screw M2.5X6.0 2
2010CU600006X Volume knob
2010CU600007X Encoder knob
7110CLP02001 CLP-02 Clip
Chapter 5 Circuit Description
5.1 Frequency configuration
The reference frequency of frequency synthesizer is provided by 12.8MHz crystal oscillator
X1 TCXO. The receiver adopts quadric mixing mode. The first IF is 38.85MHz, and the
second IF is 450kHz. The first local oscillation signal of the receiver is produced by frequency
synthesizer and the second local oscillation signal selects the 3
rd
harmonics of 12.8MHz of
crystal oscillator X1 TCXO. The signal of transmitter is produced by frequency synthesizer
directly.