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EP0106229A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Adaptive filter including controlled tap gain coefficient drift

Assignee: AT&T Inc
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Filing: 1983-09-28
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Granted: —
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Expires: 2003-09-28
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Abstract

Abstract In adaptive filters, under certain incoming signal conditions the tap gain coefficients tend to drift toward relatively large values. This condition has been countered by taking so-called leakage into account in generating the tap gain coefficients. Introduction of leakage tends to drive the tap gains toward zero and is desirable under certain incoming signal conditions and not others. Indeed, during intervals that concentrated partial or narrow band energy, e.g., single frequency tones, multifrequency tones and the like, is incoming to the filter there is a need to introduce a relatively large leakage value into the tap gain coefficients. However, during intervals when whole or wide band energy, e.g., speech or noise, is incoming to the filter no leakage is desired or needed. This is realized by detecting intervals during which partial band energy is incoming to the filter and controllably increasing the leakage value during those intervals only.

Inventors

  • 👤 Charles William Kevin Gritton

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 09:03
CPC Classifications
H; H03; H03H; H03H21/00; H03H21/0012; H03H21/0067; H04; H04B; H04B3/00; H04B3/02; H04B3/20; H04B3/23; H04B3/238

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 118 words
An adaptive filter (100) of the transversal type having a plurality of tap gain adjustment signals for incrementally delayed samples of signals being shaped including a plurality of means (119) for generating a leakage compensation component, a like plurality of means (118) for combining such leakage compensation component with such tap gain adjustment signals, and means (104) for discriminating between whole band and narrow-band energy in signals being shaped CHARACTERIZED IN THAT means (122) for combining such leakage compensation component to counter-balance an excess of tap gain adjustment signals are biased under the control of such discriminating means (104) in accordance with whether or not narrow-band energy dominates over whole band energy in the signal to be shaped.
Claim 2
Dependent Claim 118 words
An adaptive filter (100) of the transversal type having a plurality of tap gain adjustment signals for incrementally delayed samples of signals being shaped including a plurality of means (119) for generating a leakage compensation component, a like plurality of means (118) for combining such leakage compensation component with such tap gain adjustment signals, and means (104) for discriminating between whole band and narrow-band energy in signals being shaped CHARACTERIZED IN THAT means (122) for combining such leakage compensation component to counter-balance an excess of tap gain adjustment signals are biased under the control of such discriminating means (104) in accordance with whether or not narrow-band energy dominates over whole band energy in the signal to be shaped.
Claim 3
Dependent Claim 86 words
The adaptive filter (Fig. 2) set forth in claim 1 further CHARACTERIZED IN THAT the polarities of the outputs of generating means (119) correspond to those of the most recent tap gain adjustment signal, and the leakage compensation components from generating means (119) are effective in combining means (118) in the alternative when either the polarities of the most recently modified and the raw tap gain adjustment signals are opposite in polarity or the narrow-band energy exceeds the whole band energy in the signal being shaped.
Claim 4
Dependent Claim 70 words
The adaptive filter (Fig. 3) set forth in claim 1 further CHARACTERIZED IN THAT the polarities of the outputs of generating means (119) correspond to those of the most recently modified tap gain adjustment signals, and the magnitudes of the leakage compensation components from generating means (119) are proportioned in accordance with the degree of dominance of the narrow-band energy over the whole band energy in the signal being shaped.

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