The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 1998
Filed:
Jun. 28, 1996
Shigeji Ikeda, Tokyo, JP;
NEC Corporation, , JP;
Abstract
The object of the present invention is to provide a noise cancelling method and a noise canceller where the shortening of the convergence time and the reduction in the distortion (residual error) after the convergence can be realized. A second adaptive filter outputs a pseudo noise signal by receiving a reference signal from a reference signal input terminal. A subtracter subtracts an output pseudo noise signal of the second adaptive filter from a receiving signal input from a speech signal input terminal, and supplies the subtraction result to the second adaptive filter as an error signal. A divisor circuit divides an output speech signal power of a power averaging circuit obtained from the output error signal of the subtracter by an output noise signal power of another power averaging circuit obtained from the output pseudo noise signal of the second adaptive filter, and outputs the result of the division as an estimated value of the signal to noise ratio (SNR). A step size output circuit operates so as to receive the output signal of a signal to noise ratio estimating circuit as an input, and output a value corresponding to the input SNR value as the step size for a first adaptive filter.