×

Speech processing system and method for enhancing a speech signal in a noisy environment

  • US 5,590,241 A
  • Filed: 04/30/1993
  • Issued: 12/31/1996
  • Est. Priority Date: 04/30/1993
  • Status: Expired due to Term
First Claim
Patent Images

1. A method for enhancing speech signals in a noisy environment, comprising the steps of:

  • inputting a digital speech signal x(k) at an input of a plurality of successive delay elements whose outputs form a like plurality of taps of an adaptive finite impulse response (FIR) filter;

    inputting said digital speech signal and each of said plurality of taps to corresponding inputs of a plurality of variable multipliers;

    computing a first signal power estimate y(k) at a sample point k given by the formula y(k)=β

    1 y(k-1)+(1-β

    1)x2 (k);

    computing a second signal power estimate z(k) at said sample point k given by the formula z(k)=β

    2 z(k-1)+(1-β

    2)x2 (k);

    choosing a value of β

    1 greater than a value of β

    2 ;

    selecting an overall signal power estimate yz(k) at said sample point k as a maximum one of said first signal power estimate y(k) and said second signal power estimate z(k);

    recursively updating a plurality of FIR filter coefficients corresponding to said plurality of variable multipliers according to a normalized least-mean-squares (NLMS) prediction using said overall signal power estimate yz(k) and an estimation error signal to provide updated values of said plurality of FIR filter coefficients;

    providing said updated values of said plurality of FIR filter coefficients to coefficient inputs of said plurality of variable multipliers; and

    summing outputs of said plurality of variable multipliers to provide an enhanced speech signal as an output of said adaptive FIR filter.

View all claims
  • 18 Assignments
Timeline View
Assignment View
    ×
    ×