ECHO DETECTION Russian patent published in 2011 - IPC H04B3/20 

FIELD: physics.

SUBSTANCE: echo detection method involves creating a set of values of distance between estimates of the fundamental harmonic of a first signal and estimates of the fundamental harmonic a second signal with predefined delay relative the said first signal by using a hypothesis where it is assumed that the difference between estimates of the fundamental harmonic of the said first signal and estimates of the fundamental harmonic of the said second signal are random processes which follow a first predefined statistical distribution in the presence of an echo and a second predefined statistical distribution in the absence of an echo. A measure of distance corresponding to the highest similarity between the said first and second signals is selected from the said set. The said second signal is classified as one that includes an echo from the said first signal if the selected measure of distance has a predefined relationship with a predefined threshold value.

EFFECT: faster detection and estimation of delay of a delayed or possibly distorted copy of a known speech or audio signal in a mixture with noise.

26 cl, 7 dwg