Speakerphone
First Claim
1. A system comprising:
- a memory configured to store program instructions; and
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are configured to direct the processor to;
operate on samples of a digital output signal to determine samples of a digital correction signal, wherein the output signal samples are directed to an output channel for transmission from a speaker; and
supply the digital correction signal samples to a first digital-to-analog converter for conversion into an analog correction signal;
a subtraction circuit configured to generate a difference signal which is a difference between a first analog signal provided by a microphone and the analog correction signal, wherein the analog correction signal is an estimate of a contribution to the first analog signal due to a direct path transmission between the speaker and the microphone;
wherein the program instructions are further configured to direct the processor to;
receive a digital input signal derived from the difference signal; and
perform acoustic echo cancellation on the digital input signal to obtain a resultant signal, wherein the acoustic echo cancellation is configured to remove contributions to the digital input signal due to reflected path transmissions between the speaker and the microphone.
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Accused Products
Abstract
A processor operates on samples of a digital output signal to determine samples of a digital correction signal. The output signal samples are directed to an output channel for transmission from a speaker. The digital correction signal samples are supplied to a first digital-to-analog converter for conversion into an analog correction signal. The subtraction circuit generates a difference between a first analog signal provided by a microphone and the analog correction signal. The analog correction signal is an estimate of a contribution to the first analog signal due to a direct path transmission between the speaker and the microphone. The processor also receives a digital input signal derived from the difference signal, and, performs acoustic echo cancellation on the digital input signal to obtain a resultant signal. The acoustic echo cancellation is configured to remove contributions to the digital input signal due to reflected path transmissions.
309 Citations
20 Claims
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1. A system comprising:
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a memory configured to store program instructions; and
a processor configured to read and execute the program instructions from the memory, wherein the program instructions are configured to direct the processor to;
operate on samples of a digital output signal to determine samples of a digital correction signal, wherein the output signal samples are directed to an output channel for transmission from a speaker; and
supply the digital correction signal samples to a first digital-to-analog converter for conversion into an analog correction signal;
a subtraction circuit configured to generate a difference signal which is a difference between a first analog signal provided by a microphone and the analog correction signal, wherein the analog correction signal is an estimate of a contribution to the first analog signal due to a direct path transmission between the speaker and the microphone;
wherein the program instructions are further configured to direct the processor to;
receive a digital input signal derived from the difference signal; and
perform acoustic echo cancellation on the digital input signal to obtain a resultant signal, wherein the acoustic echo cancellation is configured to remove contributions to the digital input signal due to reflected path transmissions between the speaker and the microphone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method comprising:
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operating on samples of a digital output signal to determine samples of a digital correction signal, wherein the output signal samples are directed to an output channel for transmission from a speaker;
supplying the digital correction signal samples to a first digital-to-analog converter for conversion into an analog correction signal;
generating a difference signal which is a difference between a first analog signal provided by a microphone and the analog correction signal, wherein the analog correction signal is an estimate of a contribution to the first analog signal due to a direct path transmission between the speaker and the microphone;
receiving a digital input signal derived from the difference signal; and
performing acoustic echo cancellation on the digital input signal to obtain a resultant signal, wherein the acoustic echo cancellation is configured to remove contributions to the digital input signal due to reflected path transmissions between the speaker and the microphone. - View Dependent Claims (17, 18, 19)
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20. A computer-readable memory medium configured to store program instructions, wherein the program instructions are executable to implement:
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operating on samples of a digital output signal to determine samples of a digital correction signal, wherein the output signal samples are directed to an output channel for transmission from a speaker;
supplying the digital correction signal samples to a first digital-to-analog converter for conversion into an analog correction signal;
generating a difference signal which is a difference between a first analog signal provided by a microphone and the analog correction signal, wherein the analog correction signal is an estimate of a contribution to the first analog signal due to a direct path transmission between the speaker and the microphone;
receiving a digital input signal derived from the difference signal; and
performing acoustic echo cancellation on the digital input signal to obtain a resultant signal, wherein the acoustic echo cancellation is configured to remove contributions to the digital input signal due to reflected path transmissions between the speaker and the microphone.
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Specification