Angle modulated signal receiving apparatus

摘要

Local frequency, which is subject to fluctuate in a mobile subscriber set, is locked to stable transmit frequency of a base station. A mobile subscriber set (Figure 3) for receiving an angle modulated signal has a frequency mixer (3.6, 3.9), for converting a wireless receive frequency to an intermediate frequency by using a local frequency (FL1, FL2), a limiter (3.11) for limiting amplitude of intermediate frequency signal, a discriminator (3.12) for demodulating the angle modulated signal, a standard oscillator (3.1) such as a quartz crystal oscillator and a synthesizer (64) for providing the local frequency to the mixer (3.6), a digital frequency counter (3.14) for measuring intermediate frequency, and control means (3.16) for adjusting the standard oscillator (3.1) depending upon the error in intermediate frequency measured by said counter (3.14).