SIGNAL PROCESSING CIRCUIT, SIGNAL PROCESSING METHOD, IMAGING DEVICE, METHOD FOR SPEECH SIGNAL PROCESSING OF IMAGING DEVICE, RECORDING DEVICE AND RECORDING METHOD, AND REPRODUCTION DEVICE AND REPRODUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To reduce a cyclic noise of a speech signal in which a cyclic noise is included. SOLUTION: A correlation calculation is implemented for one cycle of a speech input signal (S+N) inputted in an input terminal 10 and a speech input signal of one cycle before being supplied from a buffer memory 11 at a correlation calculator 12, and a correlation coefficient C is calculated. A gain coefficient is adaptively determined at a correlation determination 13 based on the correlation coefficient C, and the speech input signal is multiplied by the gain coefficient. The speech signal multiplied by the gain coefficient is added to an addition output Y stored in a noise memory 17 for accumulation. The accumulated signal is subtracted from the speech input signal (S+N). Since the speech signal multiplied by the gain coefficient is added to the addition output Y stored in the noise memory 17, the value of the addition output Y converges to the value of the cyclic noise N. Since the gain coefficient is adaptively determined in correspondence with the correlation coefficient C, the addition output can converge more quickly and properly than when the gain coefficient is fixed. COPYRIGHT: (C)2007,JPO&INPIT