Method for real-time reduction of voice telecommunications noise not measurable at its source

Claim 1

In a telecommunications network carrying an incoming signal, said incoming signal having both speech and noise energy, a method for real-time processing of said incoming signal using an iterated filter operated as a Linear Predictive Coding speech model comprising filter-order adjustments and means for equivalently representing pole positions of said Linear Predictive Coding speech model with Line Spectral Pair position roots and difference roots, in which said iterated filter creates an estimate of the speech power spectrum component of said incoming signal for each current frame for transmission to said telecommunications network, said method comprising the steps of: converting said incoming signal to a time-series of spectral domain data frames; selecting from said time-series of data frames a subset of consecutive data frames including a group of past data frames, the current data frame and up to two future data frames; performing a selected number of iterations upon said current data frame across said subset of data frames, each said iteration generating values of said Line Spectral Pair position roots and difference roots; during said iteration sequence, for each iteration smoothing said Line Spectral Pair root positions generated for said past data frames, with the Line Spectral Pair root position of said current frame, using values of Line Spectral Pair root positions calculated for the current iteration of said sequence; creating estimates of said incoming speech power spectrum from the output of a succession of said iteration sequences of said current frames; forming a noise-reduced speech signal based on said incoming speech power spectrum estimates; and transmitting said noise-reduced speech signal to said telecommunications network.