Abstract: A delayed adaptive least-mean-square (LMS) filter, which has one filter coefficient per tap and acquires a new data sample each frame, calculates a finite impulse response (FIR) filter output and updates the filter coefficients using an error term based on the FIR filter output calculated during the preceding frame. The calculations for each tap are performed in a single clock cycle. The filter can be implemented using a general purpose, programmable digital signal processor (DSP) architecture having two multiply and accumulate circuits (MACs), with or without an arithmetic logic unit (ALU), and preferably implements its memory buffers as dual-access or dual-port RAM or banked memory.

Abstract: Method and apparatus for detecting voice activity in an audio signal, the method comprising computing the autocorrelation coefficients of the signal, identifying a first autocorrelation vector whose components comprise a first series of autocorrelation coefficients, identifying a second autocorrelation vector whose components comprise a second series of autocorrelation coefficients offset from the first series by a predetermined offset value, subtracting the first autocorrelation vector from the second autocorrelation vector to obtain a differentiation vector, and computing a norm of the differentiation vector, which differentiation vector norm represents a first indicator of voice activity.