CS800-Service-Manual维修维护说明书手册含电气原理图

DM6000-2 DM6100-2 Circuit Description1 Frequency configurationThe reference frequency of frequency synthesizer is provided by 16.8MHz crystal oscillator X3 TCXO.The receiver adopts quadric mixing mode.The first IF is 49.95MHz,and the second IF is 450kHz.Thefirst local oscillation signal of the receiver is produced by frequency synthesizer and the second localoscillation signal selects the 3d hammonics of 16.8MHz of crystal oscillator X3 TCXO.The signal oftransmitter is produced by frequency synthesizer directly450kHzD306D3070505050449.95MHE0503I1C13IC7150●501ANT SWCFIF MIX DETAF AMPANTRF AMPIF AMPAF PA51.4MHz1C10501X3BASE BANDQ4 Q6PROCESSORIC14MICTCXO,M0D2RF PAMIC AMF16.8MHzQ303IC302MOD1Figure 1 Frequency configuration2 Receiver (Rx)The receiver is double conversion superheterodyne,designed to operate in the frequency range of400 to 470MHz,The frequency configuration in Fig 203-12360311C1的c501IC1BASE BANDPROCESS0RFigure 2 Receiver section configurationFront End of ReceiverSignals from the antenna are filtered by BPF which consists of C570 C571 C573 C576 C574 L514 L515D508 and D509 via RX/TX switch (D306 D307 and D309 D311).After being filtered out the uselessout-of-band signals,the signals are amplified by LNA consisting of Q505 and external components.Signals from LNA are filtered again by BPF which consists of C557 C553 L510 L511 D505 D506 and