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US 5,206,854 AGranted
Detecting loss of echo cancellation
AssigneeAT&T Bell Laboratories
InventorsWilliam L. Betts, Robert A. Day, II
Life of this patent
Estimating the term…
Abstract
In a full-duplex modem, correlation of an echo estimate signal with an echo-canceled signal is used to determine the presence or absence of a remote signal.
Claims5
A method comprising the steps of
- receiving a signal,
- subtracting an echo estimate signal from the received signal to provide an echo-canceled signal,
- correlating the echo estimate signal with the echo-canceled signal to provide a degree of correlation, and
- determining the absence of a remote signal by detecting the degree of correlation of the echo estimate signal with the echo-canceled signal.
1 more element
Apparatus comprising
- means for receiving a signal,
- means for subtracting an echo estimate signal from the received signal to provide an echo-canceled signal,
- means for correlating the echo estimate signal with the echo-canceled signal to provide a signal representative of the degree of correlation, and
- means for receiving the signal representative of the degree of correlation to determine the presence or absence of a remote signal.
1 more element
Modem apparatus comprising
- means for transmitting a first signal,
- means for receiving a second signal,
- echo canceler means to provide an echo estimate signal representative of the first signal,
- means for combining the echo estimate signal and the second signal to provide an echo-canceled signal,
- means for correlating the echo estimate signal with the echo-canceled signal to provide a signal representative of the degree of correlation, and
- means for receiving the signal representative of the degree of correlation to determine the presence or absence of a remote signal.
3 more elements
Dependencies are inferred from the claim text.