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US 7,627,025 B2Granted
Echo canceller gain control for channel diagnostic systems
AssigneeBroadcom Corporation
InventorsPeiqing Wang, Scott R. Powell
Life of this patent
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Abstract
A method and apparatus for detecting faults in cables. The method and apparatus comprise receiving a reflected signal; multiplying an estimation of the reflected signal from an echo canceller by a predetermined gain factor; subtracting the value obtained as a result of the multiplication from the received reflected signal; and generating an error signal to adapt the echo canceller tap weight to match the real received reflected signal.
Claims16
A method for detecting faults in cables, comprising:
- a) transmitting a transmitted signal on a cable;
- b) receiving a reflected signal from the cable;
- c) determining a multiplied echo canceller output, including multiplying an output of an echo canceller by an echo canceller gain factor;
- d) converging a plurality of echo canceller coefficients based on the reflected signal to adapt the multiplied echo canceller output to approximate the reflected signal,
- wherein each echo canceller coefficient of the plurality of echo canceller coefficients corresponds to a respective tap of a plurality of taps of the echo canceller;
- e) comparing a value of an echo canceller coefficient, of the plurality of echo canceller coefficients, corresponding to a given tap, of the plurality of taps, to a corresponding threshold,
- wherein the corresponding threshold is based on a piecewise linear function of a tap number associated with the given tap;
- and
- f) repeating step e) for each remaining tap of the plurality of taps.
6 more elements
An apparatus, comprising:
- an echo canceller comprising
- means for converging a plurality of coefficients based on an error signal, wherein each coefficient of the plurality of coefficients corresponds to a respective tap of a plurality of taps;
- a multiplier coupled to the echo canceller and configured to multiply an output of the echo canceller by an echo canceller gain factor;
- a summation node coupled to the echo canceller and the multiplier, and configured to generate the error signal, comprising subtracting the output of the multiplier from a reflected signal;
- means for determining a plurality of thresholds, wherein each threshold is determined based on a piecewise linear function of a tap number of a respective tap of the plurality of taps;
- and
- means for detecting a cable fault based on a comparison of a coefficient of the plurality of coefficients to a respective threshold of the plurality of thresholds, wherein the respective threshold for each coefficient was determined based on a tap number of the respective tap corresponding to the coefficient.
4 more elements
Dependencies are inferred from the claim text.