Echo cancellation with quantization compensation
AssigneeAvago Technologies General IP (Singapore) Pte. Ltd.
InventorDavid G. Shaw
Life of this patent
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Abstract
An apparatus having a first circuit and a second circuit is disclosed. The first circuit is configured to generate a first intermediate signal by expanding a first input signal subjected to a quantization. The second circuit is configured to generate a second intermediate signal based on a second input signal. The second intermediate signal approximates an echo in the first input signal caused by the second input signal. The second circuit is also configured to generate a third intermediate signal by companding the second intermediate signal to compensate the quantization of the first input signal.
Claims20
An apparatus comprising:
- a control circuit configured to generate one or more selective control signals;
- a first circuit configured to generate a first intermediate signal by expanding a first input signal subjected to a quantization;
- and
- a second circuit configured to (i) generate a second intermediate signal based on a second input signal, wherein said second intermediate signal approximates an echo in said first input signal caused by said second input signal, and (ii) generate a third intermediate signal by selectively companding said second intermediate signal to compensate said quantization of said first input signal, said selective companding a result of receiving a selective control signal, wherein said first circuit and said second circuit are implemented as hardware or a combination of hardware and software.
A method for echo cancellation with quantization compensation, comprising the steps of:
- generating a first intermediate signal by expanding a first input signal subjected to said quantization;
- generating a second intermediate signal based on a second input signal, wherein said second intermediate signal approximates an echo in said first input signal cause by said second input signal;
- generating one or more selective control signals;
- and
- generating a third intermediate signal by selectively companding said second intermediate signal to compensate said quantization of said first input signal, wherein said selective companding is based on a selective control signal.
An echo canceller circuit comprising:
- an exapander block configured to generate a first intermediate signal by expanding a first input signal subjected to a quantization, said quantization being according to A-law or μ-law to reduce bandwidth required to transmit said first input signal;
- a first compander block and a filter block in communication with said expander block to generate a second intermediate signal based on a second input signal, wherein said first compander block compresses and expands said second input signal to generate said second intermediate signal, and wherein said second intermediate signal approximates an echo in said first input signal caused by said second input signal;
- and
- a second compander block in communication with first compander block and said filter block to generate a third intermediate signal by companding said second intermediate signal to compensate said quantization of said first input signal, and wherein said expander block, said first compander block, said filter block and said second compander block are implemented as hardware or a combination of hardware and software.
Dependencies are inferred from the claim text.