US 5,631,900 A · Double-Talk detector for echo canceller

Abstract

A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE value is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERLE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end.

Claims26

Dependent claims

A double-talk detector for an echo canceller for selectively inhibiting the operation of an adaptive filter with coefficients that are updated and the echo canteller having an Echo Return Loss Enhancement (ERLE) value associated therewith, comprising:

an ERLE processor for calculating the current ERLE of the echo canceller;
a SERLE register for storing an ERLE value as a SERLE value and having a saved ERLE input connected to the output of said ERLE processor and an output;
a comparator for comparing the output of said ERLE processor with a value and, if less, then storing the output of said ERLE processor in said SERLE register;
and
a modification device for modifying the SERLE value stored in said register upon the occurrence of a predetermined event.

2 more elements

A method for operating a double-talk detector for an echo canceller to selectively inhibit the operation of an adaptive filter with coefficients that are updated, the echo canceller having an Echo Return Loss Enhancement (ERLE) value associated therewith, comprising the steps of:

calculating the current ERLE of the echo canceller with an ERLE processor;
storing an ERLE value as a SERLE value in a SERLE register, the ERLE value stored being the best ERLE value calculated by the ERLE processor;
comparing the calculated ERLE value calculated by the ERLE processor with a value and, if less, providing a true comparison output and then storing the calculated ERLE value that was the subject of the step of comparing in the SERLE register;
and
modifying the SERLE value stored in the SERLE register upon the occurrence of a predetermined event.

2 more elements

Dependencies are inferred from the claim text.

Double-Talk detector for echo canceller

Life of this patent

Double-Talk detector for echo canceller

Life of this patent

Abstract

Claims26