Demodulator for combined digital amplitude and phase keyed modulation
signals
    6.
    发明授权
    Demodulator for combined digital amplitude and phase keyed modulation signals 失效
    用于组合数字振幅和相关键调制信号的解调器

    公开(公告)号:US4039961A

    公开(公告)日:1977-08-02

    申请号:US611545

    申请日:1975-09-08

    摘要: A digital carrier signal demodulation circuit is used in the carrier digital transmission system utilizing a 16-ary APK (Amplitude and Phase Keying) signal produced by the vector superposition of a second path signal consisting of a four-phase shift keying signal upon each phase of a first path signal consisting of a four-phase shift keying signal, the level of the second path signal being lower than that of the first path signal. The received 16-ary APK signal is detected with the reference carrier extracted from the received signal, regenerated to reproduce the base band pulses of the first path signal. The recovered base band pulses remodulate the reference carrier to produce the first path signal. The phases of the recovered first path signal and received signal are compared to phase lock a voltage controlled oscillator thereby producing the reference character.