EP0719028A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optimization of adaptive filter tap settings for subband acoustic echo cancellers in teleconferencing
Assignee: AT&T Inc
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Filing: 1995-12-06
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Granted: —
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Expires: 2015-12-06
Abstract
Abstract A subband acoustic echo canceller for a telecommunications teleconferencing room is equiped with subband adaptive filters and filter taps associated with said subbands. A data store is provided containing a weight list for controlling allocation of the filter taps among the subbands. An optimum tap profile as determined by the weights is a composite of room acoustic impulse response and weighting adjustments based on one or more measures of perceived human acoustic sensitivity experienced by far-end users. An active periodic adjustment of the weights responsive to detection of sibilant energy in the incoming path further improves echo cancellation. Active measurement and updating of the room acoustic impulse response provides further refinement. <IMAGE>
Inventors
- 👤 Eric John Diethorn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:44
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/08; H04M9/082; H04M3/00; H04M3/002; H04M3/42; H04M3/56; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
65 words
A subband acoustic echo canceller for a telecommunications teleconferencing room connected to a far-end station through incoming and outgoing signal paths, said canceller comprising: a plurality of adaptive filter taps connected to said subbands; and means for allocating said taps among said subbands based on weighting functions which are a composite of both physical acoustic factors of said room and of perceived human sensitivity factors.
Claim 2
Dependent Claim
96 words
Apparatus in accordance with Claim 1, wherein said allocating means comprises: data store means for establishing a tap weight profile for said subbands; and means for inputting to said data store means a first set of fixed data related to the acoustic impulse response function of said room, and a second set of fixed data relating to the relative speech power spectrum for male and female speakers, said first and second sets of fixed data being incorporated into said tap weights thereby to concentrate said taps in the peak energy containing lower ones of said subbands.
Claim 3
Dependent Claim
46 words
Aparatus in accordance with Claim 2, further comprising means for detecting sibilant energy in said incoming path, and means for converting said detected sibilant energy into a temporary adjustment of said fixed data-based tap weight profile, to momentarily concentrate taps in subbands containing said sibilant energy.
Claim 4
Dependent Claim
69 words
Aparatus in accordance with Claim 2, further comprising: means for detecting sibilant energy in said incoming path originating at said far-end station; means for converting said detected sibilant energy into a further adjustment of said tap weight profile to temporarily increase the taps allocated to frequencies characteristic of said detected sibilant energy; and means for returning said tap weights to their previous values following passage of said sibilant energy.
Claim 5
Dependent Claim
136 words
A subband acoustic echo canceller for a telecommunications teleconferencing room having incoming and outgoing signal paths connecting said room to one or more far-end stations, said echo canceller comprising: a plurality of subband adaptive filters; a plurality of adaptive filter taps associated with said subbands; a data store containing a weight list for controlling allocation of said taps among said subbands; means for estimating the acoustic impulse response of said room and for condensing same to a desired subband filter tap profile; means including said weight list for computing an optimum tap profile based on said desired tap profile which includes adjustments based on one or more measures of perceived human acoustic sensitivity experienced by the far-end users; and means for applying said computed optimum tap profile to said subband adaptive filters of said echo canceller.
Claim 6
Dependent Claim
46 words
A subband acoustic echo canceller in accordance with Claim 5, further comprising means for impressing onto said data store weight list indicia of human speech power weightings to concentrate at least some available filter taps to subbands operating at frequencies at and below substantially 1000 Hz.
Claim 7
Dependent Claim
25 words
An echo canceller in accordance with Claim 6, further comprising means for impressing onto said data store weight list indicia of human hearing sensitivity weightings.
Claim 8
Dependent Claim
36 words
An echo canceller in accordance with Claim 6, further comprising means for impressing onto said data store weight list an adjustment that is a product of human hearing sensitivity weighting and of long-term speech power weighting.
Claim 9
Dependent Claim
36 words
An echo canceller in accordance with Claim 8, further comprising means for impressing onto said data store weight list indicia of echo perception weightings representative of the human ear's sensitivity to echoes of relatively longer delay.
Claim 10
Dependent Claim
70 words
An echo canceller in accordance with Claims 5, 6, 7, 8, or 9, further comprising: means for detecting sibilant energy in said incoming path; means for converting said detected sibilant energy into a further adjustment of said weight list to temporarily increase the taps allocated to frequencies characteristic of said detected sibilant energy; and means for returning said tap weights to their previous values following passage of said sibilant energy.
Claim 11
Dependent Claim
33 words
An echo canceller in accordance with Claim 10, further comprising means for actively periodically measuring the acoustic impulse response of said room and for condensing same to said desired subband filter tap profile.
References Cited (Backward Citations)
No citation records indexed.
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