公开(公告)号：FR2733345A1

公开(公告)日：1996-10-25

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

Abstract: A system for low rate coding or decoding includes the use of a mode indicator in the coded signal to indicate whether prequantizer (i.e., coarse) or quantizer (i.e., fine) information is being sent. In a transmitter (300) embodiment both a prequantizer (212) and a restricted quantizer (214) search is performed of predefined prequantizer ("P") and quantizer ("V") codewords, respectively, to determine the codewords with the least residual energy. The index of the P or V codeword with the least residual is then determined (220), and this index is transmitted along with an appropriate P or V mode indicator. In a receiver (330) embodiment, the mode indicator is used to set the decoder (e.g., a vocoder) (350) to form a signal replica from a P codeword (determined from the transmitted index), or from a V codeword (from the transmitted V index) and previously determined P codeword (e.g., the centroid of the V codeword).

公开(公告)号：BRPI0818047A2

公开(公告)日：2015-03-31

申请号：BRPI0818047

申请日：2008-09-23

Applicant: MOTOROLA INC

Inventor： MITTAL UDAR ,  ASHLEY JAMES P

IPC: H03M7/30

公开(公告)号：DE19681070C2

公开(公告)日：2002-10-24

申请号：DE19681070

申请日：1996-09-04

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: H04B1/10 ,  G10L21/02 ,  H04B15/00 ,  H04Q7/20 ,  H04B7/005 ,  H04B17/00 ,  H04B7/204

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：BR0016127A

公开(公告)日：2002-08-06

申请号：BR0016127

申请日：2000-11-30

Applicant: MOTOROLA INC

Inventor： RAMABADRAN TENKASI V ,  ASHLEY JAMES P

IPC: H04B3/06 ,  G10L21/02 ,  H04B15/00 ,  H04S1/00

Abstract: A method and apparatus for suppressing acoustic background noise in a communication system. An operating signal-to-noise ratio (SNR) level is reliably evaluated from channel energy (293) and background noise energy (294) values by a SNR level estimator (295). A minimum gain factor and a gain slope are adapted (290) depending on the operating SNR level. Using these adapted values and the channel SNR, the channel gain is selected (233). When the channel SNR is below a certain threshold, the channel is completely noise-like and the gain factor selected is minimum so that the channel is maximally attenuated. When the channel SNR is fairly high, the channel gain selected is 0 dB. For intermediate values of channel SNR, the gain factor selected lies between minimum and 0 dB.

公开(公告)号：BR9807961A

公开(公告)日：2000-03-08

申请号：BR9807961

申请日：1998-02-18

Applicant: MOTOROLA INC

Inventor： DECLERCK DANIEL J ,  ASHLEY JAMES P

IPC: H04W28/06 ,  H04W36/08 ,  H04B7/216 ,  H04Q7/00

Abstract: A mobile station (106) in a code division multiple access (CDMA) communication system (100) implements scanning of pilot channels on a different frequency by reserving a periodic frame on the forward channel to allow the mobile station (106) to change frequencies and scan for other pilot channels. To preserve some aspects of voice quality, both the base station (102) and mobile station (106) voice encode speech at a maximum of half rate and transmit the information as secondary traffic prior to the frame where the mobile station (106) scans the alternate frequency. To maximize the trade-off between voice quality and frequency of the scan, the base station (102) indicates to the mobile station (106) the period between other frequency scans via messaging. To ensure compatibility, this method can be negotiated via known service configuration negotiation techniques.

公开(公告)号：HK1005112A1

公开(公告)日：1998-12-24

申请号：HK98104250

申请日：1998-05-18

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: G10L21/02 ,  H04B1/10 ,  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：CA2247429A1

公开(公告)日：1998-07-30

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) directly into a noise suppression system (403). The noise suppression system (403) uses 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 residual 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：DE19681070T1

公开(公告)日：1998-02-26

申请号：DE19681070

申请日：1996-09-04

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

IPC: H04B1/10 ,  G10L21/02 ,  H04B15/00 ,  H04Q7/20 ,  H04B7/005 ,  H04B17/00 ,  H04B7/204

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：SE9701659L

公开(公告)日：1997-09-12

申请号：SE9701659

申请日：1997-05-02

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P

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

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：CA2093744C

公开(公告)日：1997-07-01

申请号：CA2093744

申请日：1993-04-08

Applicant: MOTOROLA INC

Inventor： ASHLEY JAMES P ,  NGUYEN QUOC

IPC: H04B3/23 ,  H04B7/015 ,  H04B3/20 ,  H04B3/21

Abstract: A method is described of decreasing convergence time in an adaptive echo canceller (20). The method includes the step of locating a primary echo within a filter vector based upon relative tap values within the filter vector. The filter vector is then narrowed, based upon the located taps. An estimated error is determined based, in part, upon the narrowed filter vector. An updated filter vector is produced based, in part, upon the estimated error.