FILTER CIRCUIT, FM TRANSMITTER INCLUDING THE SAME, AND ELECTRONIC EQUIPMENT USING FILTER CIRCUIT AND FM TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To solve the problem that, when a limiter circuit is operated, the waveform of an audio signal is distorted rectangularly and sound quality is extremely deteriorated.;SOLUTION: A pre-emphasis filter 12 emphasizes the high band component of an input audio signal S1. A limiter circuit 14 detects that the output signal of the pre-emphasis filter 12 reaches a predetermined upper limit level. When a limit operation is generated in the limiter circuit 14, a filter adjusting circuit 16 changes frequency characteristics of the pre-emphasis filter 12.;COPYRIGHT: (C)2008,JPO&INPIT