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US5513265A Expired / Lapsed US ⏱️ 0.0 years remaining

Multi-channel echo cancelling method and a device thereof

Assignee: NEC Corp
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Filing: 1994-05-31
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Granted: 1996-04-30
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Expires: 2014-05-31
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Abstract

Abstract The present invention relates to a multi-channel echo cancelling art enabling proper operation even if using a microphone not generating propagation delay difference between channels. The present invention comprises: a step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power; a step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of the reception channels based on a reception signal of the reception channel selected in the previous step; and a step of cancelling the echoes from mixed signals in which the echoes are mixed by subtracting the echo replicas from the mixed signals.

Inventors

  • 👤 Akihiro Hirano

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 06:04
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/08; H04M9/082; G; G10; G10K; G10K2210/00; G10K2210/10; G10K2210/108; G10K2210/30; G10K2210/301; G10K2210/3012; G10K2210/50; G10K2210/505

Claims Analysis

Total Claims: 38
Claim 1
Independent Claim 99 words
A multi-channel echo cancelling method comprising: a step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power; a step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel; and a step of cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 2
Dependent Claim 99 words
A multi-channel echo cancelling method comprising: a step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power; a step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel; and a step of cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 3
Dependent Claim 56 words
The multi-channel echo cancelling method of claim 1, wherein said step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power calculates a square value of reception signal in each reception channel and selects a reception channel having the biggest square value.
Claim 4
Dependent Claim 56 words
The multi-channel echo cancelling method of claim 1, wherein said step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power calculates an instantaneous power of reception signal in each reception channel and selects a reception channel having the biggest instantaneous power.
Claim 5
Dependent Claim 60 words
The multi-channel echo cancelling method of claim 1, wherein said step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power calculates a mean value of powers of reception signals in each reception channel and selects a reception channel having the biggest mean value of powers.
Claim 6
Dependent Claim 59 words
The multi-channel echo cancelling method of claim 1, wherein said step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power calculates powers of reception signals in each reception channel, sorts the results and selects a reception channel having the biggest median value of powers.
Claim 7
Dependent Claim 58 words
The multi-channel echo cancelling method of claim 1, wherein said step of calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power calculates a mode of powers of reception signals in each reception channel and selects a reception channel having the biggest mode of powers.
Claim 8
Dependent Claim 81 words
The multi-channel echo cancelling method of claim 1, wherein said step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel supplies said reception signal of the selected reception channel to adaptive filters that are one-to-one corresponding to said mixed signals and generates said echo replicas using said adaptive filters.
Claim 9
Dependent Claim 101 words
A multi-channel echo cancelling method comprising: a step of calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value; a step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel; and a step of cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 10
Dependent Claim 101 words
A multi-channel echo cancelling method comprising: a step of calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value; a step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel; and a step of cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 11
Dependent Claim 64 words
The multi-channel echo cancelling method of claim 8, wherein said step of calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value calculates a mean value of absolute values of reception signals in each reception channel and selects a reception channel having the biggest mean value of absolute values.
Claim 12
Dependent Claim 63 words
The multi-channel echo cancelling method of claim 8, wherein said step of calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value calculates absolute values of reception signals in each reception channel, sorts the results and selects a reception channel having the biggest median value of absolute values.
Claim 13
Dependent Claim 63 words
The multi-channel echo cancelling method of claim 8, wherein said step of calculating an absolute value of a reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value calculates a mode of absolute values of reception signals in each reception channel and selects a reception channel having the biggest mode of absolute values.
Claim 14
Dependent Claim 81 words
The multi-channel echo cancelling method of claim 8, wherein said step of generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected in the previous step for each reception channel supplies said reception signal of the selected reception channel to adaptive filters that are one-to-one corresponding to said mixed signals and generates said echo replicas using said adaptive filters.
Claim 15
Dependent Claim 104 words
A multi-channel echo cancelling device comprising: a reception signal selection means for calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power; a means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected by said reception signal selection means for each reception channel; and a means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 16
Dependent Claim 104 words
A multi-channel echo cancelling device comprising: a reception signal selection means for calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power; a means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected by said reception signal selection means for each reception channel; and a means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 17
Dependent Claim 118 words
The multi-channel echo cancelling device of claim 13, wherein said means for calculating a power of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest power comprises: a plurality of power calculation means, one-to-one corresponding to each reception signal, for calculating a power of reception signal of said reception channel; a reception channel selection means for selecting a reception channel having the biggest power of reception signal based on the calculation result from said power calculation means; and a selection means for receiving reception signals of reception channels and outputting a reception signal of a selected reception channel based on the selected result by said reception channel selection means.
Claim 18
Dependent Claim 35 words
The multi-channel echo cancelling device of claim 14, wherein said power calculation means comprises a multiplication means for receiving a reception signal of said reception channel and squaring this reception signal and outputting a result.
Claim 19
Dependent Claim 61 words
The multi-channel echo cancelling device of claim 14, wherein said power calculation means comprises: a multiplication means for receiving a reception signal of said reception channel and squaring this reception signal and outputting a result; and a mean calculation means for storing square values calculated by said multiplication means and calculating a mean power of reception signal from said square values.
Claim 20
Dependent Claim 70 words
The multi-channel echo cancelling device of claim 14, wherein said power calculation means comprises: a multiplication means for receiving a reception signal of said reception channel and squaring this reception signal and outputting a result; a register means for storing square values calculated by said multiplication means; and a sorting means for sorting square values stored in said register means and outputting an median value of the sorted square values.
Claim 21
Dependent Claim 82 words
The multi-channel echo cancelling device of claim 14, wherein said power calculation means comprises: a multiplication means for receiving a reception signal of said reception channel and squaring this reception signal and outputting a result; a register means for storing square values calculated by said multiplication means; a histogram means for calculating a histogram from square values stored in said register means; and a maximum value detection means for outputting a representative value of a zone having maximum value in said histogram.
Claim 22
Dependent Claim 62 words
The multi-channel echo cancelling device of claim 13, wherein said means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels, based on said reception signal of the reception channel selected by said reception signal selection means, comprises a plurality of adaptive filters one-to-one corresponding to said mixed signals.
Claim 23
Dependent Claim 22 words
The multi-channel echo cancelling device of claim 19, wherein said adaptive filter is an adaptive transversal filter based on the LMS algorism.
Claim 24
Dependent Claim 23 words
The multi-channel echo cancelling device of claim 19, wherein said adaptive filter is an adaptive transversal filter based on the learning identification method.
Claim 25
Dependent Claim 53 words
The multi-channel echo cancelling device of claim 14, wherein said means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel comprises a plurality of subtraction means, one-to-one corresponding to said mixed signals, for subtracting said echo replica from said mixed signal.
Claim 26
Dependent Claim 103 words
A multi-channel echo cancelling device comprising: a means for calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value; a means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected by said reception signal selection means for each reception channel; and a means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 27
Dependent Claim 103 words
A multi-channel echo cancelling device comprising: a means for calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value; a means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected by said reception signal selection means for each reception channel; and a means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel.
Claim 28
Dependent Claim 124 words
The multi-channel echo cancelling device of claim 23, wherein said means for calculating an absolute value of reception signal in each reception channel and selecting a reception channel of a reception signal having the biggest absolute value comprises: a plurality of absolute value calculation means, one-to-one corresponding to each reception signal, for calculating an absolute value of reception signal of said reception channel; a reception channel selection means for selecting a reception channel having the biggest absolute value of reception signal based on the calculation result from said absolute value calculation means; and a selection means for receiving reception signals of reception channels and outputting a reception signal of a selected reception channel based on the selected result by said reception channel selection means.
Claim 29
Dependent Claim 69 words
The multi-channel echo cancelling device of claim 24, wherein said absolute value calculation means comprises: an absolute value calculation means for calculating an absolute value of a reception signal of said reception channel for each reception channel; and a mean calculation means for storing absolute values calculated by said absolute value calculation means and calculating a mean value of absolute values of a reception signal from said absolute values.
Claim 30
Dependent Claim 74 words
The multi-channel echo cancelling device of claim 24, wherein said absolute value calculation means comprises: an absolute value calculation means for calculating an absolute value of a reception signal of said reception channel for each reception channel; a register means for storing absolute values calculated by said absolute value calculation means; and a sorting means for sorting absolute values stored in said register means and outputting an median value of the sorted square values.
Claim 31
Dependent Claim 86 words
The multi-channel echo cancelling device of claim 23, wherein said absolute value calculation means comprises: an absolute value calculation means for calculating an absolute value of a reception signal of said reception channel for each reception channel; a register means for storing absolute values calculated by said absolute value calculation means; a histogram means for calculating a histogram from absolute values stored in said register means; and a maximum value detection means for outputting a representative value of a zone having maximum value in said histogram.
Claim 32
Dependent Claim 62 words
The multi-channel echo cancelling device of claim 23, wherein said means for generating an echo replica corresponding to an echo in each mixed signal generated by propagation of reception signals of said reception channels based on said reception signal of the reception channel selected by said reception signal selection means comprises a plurality of adaptive filters one-to-one corresponding to said mixed signals.
Claim 33
Dependent Claim 22 words
The multi-channel echo cancelling device of claim 28, wherein said adaptive filter is an adaptive transversal filter based on the LMS algorism.
Claim 34
Dependent Claim 23 words
The multi-channel echo cancelling device of claim 28, wherein said adaptive filter is an adaptive transversal filter based on the learning identification method.
Claim 35
Dependent Claim 53 words
The multi-channel echo cancelling device of claim 23, wherein said means for cancelling said echo from said mixed signal by subtracting said echo replica from said mixed signal for each reception channel comprises a plurality of subtraction means, one-to-one corresponding to said mixed signals, for subtracting said echo replica from said mixed signal.
Claim 36
Dependent Claim 155 words
A multi-channel echo cancelling device comprising: a plurality of power calculation means, one-to-one corresponding to each reception signal, for calculating a power of reception signal of said reception channel; a reception channel selection means for selecting a reception channel having the biggest power of reception signal based on the calculation result from said power calculation means; a selection means for receiving reception signals of reception channels and outputting a reception signal of a selected reception channel based on the selected result by said reception channel selection means; a plurality of adaptive filters, one-to-one corresponding to mixed signals in which echoes generated by propagation of reception signals of said reception channels are mixed, for generating echo replicas corresponding to said echoes based on a reception signal supplied by said selection means; and a plurality of subtraction means, one-to-one corresponding to said mixed signals, for outputting a result by subtracting said echo replicas from said mixed signals.
Claim 37
Dependent Claim 155 words
A multi-channel echo cancelling device comprising: a plurality of power calculation means, one-to-one corresponding to each reception signal, for calculating a power of reception signal of said reception channel; a reception channel selection means for selecting a reception channel having the biggest power of reception signal based on the calculation result from said power calculation means; a selection means for receiving reception signals of reception channels and outputting a reception signal of a selected reception channel based on the selected result by said reception channel selection means; a plurality of adaptive filters, one-to-one corresponding to mixed signals in which echoes generated by propagation of reception signals of said reception channels are mixed, for generating echo replicas corresponding to said echoes based on a reception signal supplied by said selection means; and a plurality of subtraction means, one-to-one corresponding to said mixed signals, for outputting a result by subtracting said echo replicas from said mixed signals.
Claim 38
Dependent Claim 34 words
The multi-channel echo cancelling device of claim 32, wherein said power calculation means is substituted by said absolute value calculation means for calculating an absolute value of a reception signal of said reception channel.

References Cited (Backward Citations)

JPS6412728A Cited
US5305309A Cited
US5371789A Cited
US5323459A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1999-04-30 1999-10-30 2000-04-30 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2003-04-30 2003-10-30 2004-04-30 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2007-04-30 2007-10-30 2008-04-30 $7700.00 Window Closed / Lapsed

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