Vorrichtung zur automatischen Verstärkungsregelung

摘要

An automatic gain control apparatus comprises a variable gain amplifier 5 amplifying a signal with an amplification factor and a gain controller 6 controlling the amplification factor of the variable gain amplifier 5. A gain limiter 7 is provided for restricting the magnitude of said amplification factor within a predetermined range. The amplification factor therefore does not vary largely, even immediately after the input signal level is suddenly changed due to switching of transmitter antenna or carrier frequency. Thus, it becomes possible to quickly respond to the change of input signal without requiring a large dynamic range in the circuit following the automatic gain control apparatus.