System and Method for Acoustic Echo Removal (AER)
First Claim
1. An acoustic echo removal system comprising:
- a transmit path configured to propagate a transmit signal between a microphone and at least one voice processor, the transmit signal comprising a high-frequency portion and a low-frequency portion;
a receive path configured to propagate a receive signal between the at least one voice processor and a speaker, the receive signal comprising a high-frequency portion and a low-frequency portion;
a first acoustic echo removal portion configured to determine a first variable attenuation gain and to provide the first variable attenuation gain to the low-frequency portion of the transmit signal at a first sample frequency and to provide a second variable attenuation gain to the low-frequency portion of the receive signal at the first sample frequency; and
a second acoustic echo removal portion configured to provide the first variable attenuation gain to the high-frequency portion of the transmit signal at a second sample frequency and to provide the second variable attenuation gain to both the high-frequency portion of the receive signal and a copy of the low-frequency portion of the receive signal at the second sample frequency, the second sample frequency being greater than the first sample frequency.
1 Assignment
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Accused Products
Abstract
One embodiment of the present invention includes an acoustic echo removal system. A transmit signal and a receive signal each having high and low frequency portions, are propagated between a microphone and at least one voice processor. A first acoustic echo removal portion determines and provides a first variable attenuation gain to the low-frequency portion of the transmit signal at a first sample frequency and provides a second variable attenuation gain to the low-frequency portion of the receive signal at the first sample frequency. A second acoustic echo removal portion provides the first variable attenuation gain to the high-frequency portion of the transmit signal at a second sample frequency and provides the second variable attenuation gain to both the high-frequency portion of the receive signal and a copy of the low-frequency portion of the receive signal at the second sample frequency.
31 Citations
29 Claims
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1. An acoustic echo removal system comprising:
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a transmit path configured to propagate a transmit signal between a microphone and at least one voice processor, the transmit signal comprising a high-frequency portion and a low-frequency portion; a receive path configured to propagate a receive signal between the at least one voice processor and a speaker, the receive signal comprising a high-frequency portion and a low-frequency portion; a first acoustic echo removal portion configured to determine a first variable attenuation gain and to provide the first variable attenuation gain to the low-frequency portion of the transmit signal at a first sample frequency and to provide a second variable attenuation gain to the low-frequency portion of the receive signal at the first sample frequency; and a second acoustic echo removal portion configured to provide the first variable attenuation gain to the high-frequency portion of the transmit signal at a second sample frequency and to provide the second variable attenuation gain to both the high-frequency portion of the receive signal and a copy of the low-frequency portion of the receive signal at the second sample frequency, the second sample frequency being greater than the first sample frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An acoustic echo removal system comprising:
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a receive-path bandsplitter configured to split a receive signal into a high-frequency portion, a low-frequency portion, and a copy of the low-frequency portion; a receive-path downsampler configured to reduce a sample frequency associated with the low-frequency portion of the receive signal from a first sample frequency to a second sample frequency; a receive-path portion of a non-linear processor configured to apply a receive attenuation gain to the low-frequency portion of the receive signal at the second sample frequency; a receive-path attenuator configured to apply the receive attenuation gain to both the high-frequency portion of the receive signal and the copy of the low-frequency portion of the receive signal; and a receive-path adder configured to add the high-frequency portion and the copy of the low-frequency portion of the receive signal to generate an attenuated receive signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of removing acoustic echo in a voice communication device, the method comprising:
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bandsplitting a transmit signal into a high-frequency portion and a low-frequency portion; subtracting a compensation component from the high-frequency portion of the transmit signal, the compensation component comprising distortion associated with at least one of normalization, downsampling, upsampling, and low-pass filtering of the low-frequency portion of the transmit signal; downsampling the low-frequency portion of the transmit signal from a first sample frequency to a second sample frequency; applying a first variable attenuation gain on the low-frequency portion of the transmit signal at the second sample frequency and on the high-frequency portion of the transmit signal at the first sample frequency; upsampling the low-frequency portion of the transmit signal from the second sample frequency to the first sample frequency; and adding the low-frequency portion and the high-frequency portion of the transmit signal to generate an attenuated transmit signal, such that the attenuated transmit signal is a substantially identical reconstruction of the transmit signal. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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Specification