JPS5763937A - Noise suppression system - Google Patents

Abstract

PURPOSE:To improve an S/N ratio by putting two input signals in phase and adding them synchronously by providing a delay equalizing means in front of an adaptive filter which depends upon a coefficient of frequency correlation. CONSTITUTION:A sound from one signal source 34 is acquired by microphones 32 and 33, whose signals are supplied to terminals 24 and 25. The input signals to the terminals 24 and 25 are A/D-converted 26 and 27 and the resulting signals are supplied to a delay equalizing stage 23 to be put in phase before being inputted to an adaptive filter part 11. At the filter part 11, those two signals are separated by high-speed Fourier arithmetic circuits 14 and 15 into frequency components X1- Xn, and Z1 and Zn, which are added synchronously by an adder 18. Simultaneously, a correlation coefficient calculating circuit 16 finds a coefficient of correlation between the both, and the result is weighted by a weighting circuit 17 corresponding to a weight function. The output of the adder 18 is multiplied 19 by the output of the circuit 17, and the output of a noise component having no correlation is decreased and outputted; and respective frequency components are synthesized by a high-speed Fourier arithmetic circuit 21, whose output is converted into an analog signal by a DA converter 22.