| 摘要 |
PURPOSE:To reduce the number of the necessary circuits as well as to simplify the circuit constitution by demodulating only the service channel signal which had the FM pile modulation to the carrier wave of the 2N phase modulation wave, and thus to ensure the demodulation for the sufficiently good service signal. CONSTITUTION:The noise component of the input signal underwent the 2N phase modulation is filtered through reception BPF20, and clock component 8 of output pahse modulation wave 2 is extracted through clock extraction circuit 30. The synchronous shaping is given to component 8 via synchronous circuit 31 to produce sampling signal 9 and then to be applied to sample gate circuit 32 which supplies the output of filtered BPF20 via signal 9, and only the part where the phase information is kept correctly is made to pass through circuit 32 to extract synchronous reception signal 10. Furthermore, signal 10 receives the amplitude limitation at limiter circuit 33 which gives no effect to the phase information to give compression to the AM component of the input wave. Then the output of circuit 33 is applied to multiplication circuit 34 to draw out 2N multiplication output 12 of the carrier component of the input phase modulation wave. And service signal 6 demodulated by FM demodulator circuit 35 is delivered. |
