Inventors: Ishigaki, Yukinobu;
Assignee: Victor Company of Japan, Ltd. (Yokohama, JP)
Primary Examiner: Griffin; Robert L.
Assistant Examiner: Watkins; Albert W.
Attorney, Agent or Firm: Bernat; Louis
A noise reducing apparatus comprises a first variable gain control circuit for giving a level compression characteristic to an input signal by a first composite control voltage, to produce an output signal to a transmission path, a first control voltage producing circuit for dividing an output signal of the first variable gain control circuit into a plurality of frequency bands, and producing a plurality of control voltages respectively given with mutually different integration time constants for each of the divided frequency bands, a first adding circuit for respectively additionally composing the plurality of control voltages obtained from the first control voltage producing circuit, to obtain the first composite control voltage, a second variable gain control circuit for giving a level expansion characteristic complementary to the level compression characteristic to a level compressed signal obtained through the transmission path by a second composite control voltage, to produce an output signal, a second control voltage producing circuit for dividing an input signal of the second variable gain control circuit into a plurality of frequency bands, and producing a plurality of control voltages respectively given with mutually different integration time constants for each of the divided frequency bands, and a second adding circuit for respectively additionally composing the plurality of control voltages obtained from the second control voltage producing circuit, to obtain the second composite control voltage. |
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