公开(公告)号：FR2733345B1

公开(公告)日：1997-07-25

申请号：FR9603787

申请日：1996-03-27

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P ,  PENG WEIMIN ,  ZHANG PENG

IPC: G10L19/038 ,  H03M7/30 ,  G10L3/00 ,  G10L9/00 ,  H04B7/216

公开(公告)号：FR2741217A1

公开(公告)日：1997-05-16

申请号：FR9612357

申请日：1996-10-10

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: H04B1/10 ,  G10L21/02 ,  H04B15/00 ,  H04Q7/20 ,  H04Q7/06

Abstract: A noise suppression system (109) implemented in communication system (700) provides an improved update decision during instances of sudden increase in background noise level. The noise suppression system (109), inter alia, generates an update by continually monitoring the deviation of spectral energy and forcing an update based on a predetermined threshold criterion. The spectral energy deviation is determined by utilizing an element which has the past values of the power spectral components exponentially weighted. The exponential weighting is a function of the current input energy, which means the higher the input signal energy, the longer the exponential window. Conversely, the lower the signal energy, the shorter the exponential window. The noise suppression system (109) also inhibits a forced update during periods of continuous, non-stationary input signals (such as "music-on-hold").

公开(公告)号：BRPI0716773A2

公开(公告)日：2013-09-17

申请号：BRPI0716773

申请日：2007-07-24

Applicant: MOTOROLA INC

Inventor： MITTAL UDAR ,  CRUZ-ZENO EDGARDO M ,  ASHLEY JAMES P

IPC: G06F15/00

公开(公告)号：BRPI0407593A

公开(公告)日：2006-02-21

申请号：BRPI0407593

申请日：2004-12-17

Applicant: MOTOROLA INC

Inventor： JASIUK MARK A ,  RAMABADRAN TENKASI V ,  MITTAL UDAR ,  ASHLEY JAMES P ,  MCLAUGHLIN MICHAEL J

IPC: G10L19/08 ,  G10L25/90 ,  G10L11/04 ,  G10L19/00 ,  G10L19/12 ,  G10L19/10 ,  G10L19/04

Abstract: A method and apparatus for prediction in a speech-coding system extends a 1st order long-term predictor (LTP) filter, using a sub-sample resolution delay, to a multi-tap LTP filter. From another perspective, a conventional integer-sample resolution multi-tap LTP filter is extended to use sub-sample resolution delay. Such a multi-tap LTP filter offers a number of advantages over the prior-art. Particularly, defining the lag with sub-sample resolution makes it possible to explicitly model the delay values that have a fractional component, within the limits of resolution of the over-sampling factor used by the interpolation filter. The coefficients (betai's) of the multi-tap LTP filter are thus largely freed from modeling the effect of delays that have a fractional component. Consequently their main function is to maximize the prediction gain of the LTP filter via modeling the degree of periodicity that is present and by imposing spectral shaping.

公开(公告)号：CA2281696C

公开(公告)日：2004-06-22

申请号：CA2281696

申请日：1998-01-05

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: G10L21/02 ,  G10L11/02 ,  G10L19/00 ,  G10L19/14 ,  H04B14/04 ,  H04J3/00 ,  H04L29/08 ,  G10L9/00

Abstract: To accurately determine rate and voice activity in moderate-to-low signal-to-noise ratios (item 703) (SNRs) to maximize voice quality, system capacity and/or battery life, parameters from a noise suppression system are used as inputs to the rate determination function. Voice metrics are compared to thresholds (item 715) and rates are determined (items 721, 727, 730).

公开(公告)号：AU2003287595A1

公开(公告)日：2004-06-03

申请号：AU2003287595

申请日：2003-11-06

Applicant: MOTOROLA INC

Inventor： MITTAL UDAR ,  ASHLEY JAMES P ,  CRUZ EDGARDO M

IPC: G10L19/00 ,  G10L19/12 ,  G10L25/90 ,  G10L25/93 ,  G10L19/08 ,  G10L19/10 ,  G10L19/14 ,  G10L19/06 ,  G10L11/04 ,  G10L11/06

Abstract: A CELP encoder is provided that optimizes excitation vector-related parameters in a more efficient manner than the encoders of the prior art. In one embodiment, a CELP encoder optimizes excitation vector-related parameters based on a computed correlation matrix, which matrix is in turn based on a filtered first excitation vector. The encoder then evaluates error minimization criteria based on at least in part on a target signal, which target signal is based on an input signal, and the correlation matrix and generates a excitation vector-related index in response to the error minimization criteria. In another embodiment, a CELP encoder is provided that is capable of jointly optimizing and/or sequentially optimizing multiple excitation vector-related parameters by reference to a joint search weighting factor, thereby invoking an optimal error minimization process.

公开(公告)号：CA2247429C

公开(公告)日：2002-01-01

申请号：CA2247429

申请日：1997-11-04

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P ,  PROCTOR LEE M

IPC: H04M1/60 ,  H04B3/23 ,  H04M9/08 ,  H04B3/20

Abstract: An improved non-linear processor used in echo cancellation eliminates a comfort noise source (214) and instead inputs a control signal (224) directl y into a noise suppression system (403). The noise suppression system (403) us es the control signal (224) to inhibit the iterative update of the background noise estimate when the control signal (224) is active, which prevents any residual echo from biasing the noise estimate provided by the noise suppression system (403). Additionally, the control signal (224) is used by a gain calculator (533) within the noise suppression system (403) to attenuate each frequency band to the maximum allowable amount plus the current residua l channel signal-to-noise ratio (SNR). Depending on the implementation, the noise suppression system (403) models the background noise of either a user of the PSTN or a user of a mobile station.

公开(公告)号：CA2203917C

公开(公告)日：2000-06-27

申请号：CA2203917

申请日：1996-09-04

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: H04B1/10 ,  G10L21/02 ,  H04B15/00 ,  H04Q7/20

Abstract: A noise suppression system (109) implemented in communication system (700) provides an improved update decision during instances of sudden increase in background noise level. The noise suppression system (109), inter alia, generates an update by continually monitoring the deviation of spectral energy and forcing an update based on a predetermined threshold criterion. The spectral energy deviation is determined by utilizing an element which has the past values of the power spectral components exponentially weighted. The exponential weighting is a function of the current input energy, which means the higher the input signal energy, the longer the exponential window. Conversely, the lower the signal energy, the shorter the exponential window. The noise suppression system (109) also inhibits a forced update during periods of continuous, non-stationary input signals (such as "music-on-hold").

公开(公告)号：FI972852A

公开(公告)日：1997-07-03

申请号：FI972852

申请日：1997-07-03

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: H04B1/10 ,  G10L21/02 ,  H04B15/00 ,  H04Q7/20 ,  H04B

Abstract: A noise suppression system implemented in communication system provides an improved update decision during instances of sudden increase in background noise level. The noise suppression system, inter alia, generates an update by continually monitoring the deviation of spectral energy and forcing an update based on a predetermined threshold criterion. The spectral energy deviation is determined by utilizing an element which has the past values of the power spectral components exponentially weighted. The exponential weighting is a function of the current input energy, which means the higher the input signal energy the longer the exponential window. Conversely, the lower the signal energy the shorter the exponential window. The noise suppression system also inhibits a forced update during periods of continuous, non-stationary input signals (such as "music-on-hold").

公开(公告)号：FR2722627B1

公开(公告)日：1997-05-09

申请号：FR9507222

申请日：1995-06-16

Applicant: MOTOROLA INC SOCIETE DE DROIT

Inventor： ASHLEY JAMES P ,  PROCTOR LEE MICHAEL

IPC: H03H17/00 ,  H03H21/00 ,  H04B3/23

Abstract: A method and apparatus are provided for echo canceling which includes double-talk immunity. The echo canceller (15) according to the present invention includes a double-talk detector (17) which uses an adaptive double-talk detection threshold (214) and an accurate estimation of reference energy (106) to detect double-talk. The echo canceller further provides for correcting partial echo canceller adaptive filter vector divergence occurring prior to double-talk detection by maintaining and switching to an auxiliary echo canceller filter with known "good" filter coefficients (58, 60, 62).