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公开(公告)号：GB2348092B
公开(公告)日：2001-04-18
申请号：GB0000688
申请日：2000-01-12
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
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公开(公告)号：GB2348091B
公开(公告)日：2001-04-18
申请号：GB0000686
申请日：2000-01-12
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
Abstract: A subband acoustic echo canceller (120) includes an adaptation speed controller (240). The adaptation speed controller measures the energies of the echo residual signals r m (n) for each subband. Those subbands having high echo residual energies are allocated normal adaptation rates; whereas those subbands having low echo residual energies are allocated slower adaptation rates. The adaption rates are controlled by signals s m (n) sent from the adaptation speed controller (240) to adaptive filters (201, 202, 203) for the respective subbands.
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公开(公告)号：GB2342832A
公开(公告)日：2000-04-19
申请号：GB9917920
申请日：1999-08-02
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
Abstract: A double-talk detection device (400) detects the presence of near-end speech signals for an echo canceller including an adaptive filter to generate an echo estimate. A control device (300) generates the coefficients for the adaptive filter. The control device (300) includes a coefficient updating circuit (320). A buffer (314) holds the previous filter coefficients and a buffer (318) holds the current filter coefficients. The double-talk detection device (400) detects the presence of near-end speech signals based upon a detected variation of the coefficients. The detection device (400) is used to detect a double-talk condition during a single-talk condition and a single-talk condition during the double-talk condition.
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公开(公告)号：FR2739481A1
公开(公告)日：1997-04-04
申请号：FR9611654
申请日：1996-09-25
Applicant: MOTOROLA INC
Inventor： MCLAUGHLIN MICHAEL , RAMABADRAN TENKASI V
Abstract: A signal that includes noise (301) is sampled to provide a plurality of digital information samples (303). A predetermined number of the digital information samples are grouped as a set (305). Noise suppression is performed on the signal using the following steps. One or more digital representations of silence is attached to the set, forming an extended set (401). A Fourier transform is performed on the extended set, yielding a set of frequency domain coefficients (403), at least some of which are scaled (405). An inverse Fourier transform is performed on the set of scaled frequency domain coefficients to provide a set of time domain samples (407), which are partially overlapped in time and added with a previously formed set of time domain samples (409 and 411), which result is provided with the non-overlapping time domain samples as a noise suppressed version of the signal (413).
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公开(公告)号：DE3370422D1
公开(公告)日：1987-04-23
申请号：DE3370422
申请日：1983-08-02
Applicant: MOTOROLA INC
Inventor： MCLAUGHLIN MICHAEL
IPC: H04B17/00 , H04B20060101 , H04B7/08 , H04B7/26
Abstract: A method and apparatus for measuring the strength of a radio frequency (RF) signal subject to Rayleigh fading. The strength of the RF signal is sampled two or more times during a predetermined time interval and the sampled signal strength having the largest magnitude is selected. The selected signal strength is a reasonably accurate measure of the signal strength since the true average strength of a Rayleigh fading signal is close to its peak signal strength. The inventive method and apparatus is particularly well adapted for use in a scanning receiver located in a base station radio (111, 121, 131) of a cellular radiotelephone communications system. The scanning receiver includes an antenna selector (102) for selecting one of a plurality of sector antennas, an RF signal receiver (104) tunable to a plurality of different RF signal frequencies, an analog-to-digital converter (106) for converting RF signal strength samples to a binary data signal and a microprocessor (114) together with peripheral devices (108, 110, 112, 116, 118, 120) for controlling the operation of the antenna selector (102), RF signal receiver (104) and analog-to-digital converter (106).
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Patent Agency Ranking
公开(公告)号：GB2348091A
公开(公告)日：2000-09-20
申请号：GB0000686
申请日：2000-01-12
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
Abstract: A subband acoustic echo canceller (120) includes an adaptation speed controller (240). The adaptation speed controller measures the energies of the echo residual signals r m (n) for each subband. Those subbands having high echo residual energies are allocated normal adaptation rates; whereas those subbands having low echo residual energies are allocated slower adaptation rates. The adaption rates are controlled by signals s m (n) sent from the adaptation speed controller (240) to adaptive filters (201, 202, 203) for the respective subbands.
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公开(公告)号：DE19935587A1
公开(公告)日：2000-02-17
申请号：DE19935587
申请日：1999-08-02
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
Abstract: An adaptive filter is connected to receive the remote signal with corrupting echo. Its coefficients are updated. Filter coefficient variance is calculated. Should the variance reach a threshold value, presence of the phantom (or echoed) speech state is established. An Independent claim is included for the control unit carrying out the method.
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公开(公告)号：NO161890B
公开(公告)日：1989-06-26
申请号：NO841285
申请日：1984-04-02
Applicant: MOTOROLA INC
Inventor： MCLAUGHLIN MICHAEL
IPC: H04B17/00 , H04B20060101 , H04B7/08 , H04B7/26
Abstract: A method and apparatus for measuring the strength of a radio frequency (RF) signal subject to Rayleigh fading. The strength of the RF signal is sampled two or more times during a predetermined time interval and the sampled signal strength having the largest magnitude is selected. The selected signal strength is a reasonably accurate measure of the signal strength since the true average strength of a Rayleigh fading signal is close to its peak signal strength. The inventive method and apparatus is particularly well adapted for use in a scanning receiver located in a base station radio (111, 121, 131) of a cellular radiotelephone communications system. The scanning receiver includes an antenna selector (102) for selecting one of a plurality of sector antennas, an RF signal receiver (104) tunable to a plurality of different RF signal frequencies, an analog-to-digital converter (106) for converting RF signal strength samples to a binary data signal and a microprocessor (114) together with peripheral devices (108, 110, 112, 116, 118, 120) for controlling the operation of the antenna selector (102), RF signal receiver (104) and analog-to-digital converter (106).
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公开(公告)号：DK176784A
公开(公告)日：1984-04-03
申请号：DK176784
申请日：1984-04-03
Applicant: MOTOROLA INC
Inventor： MCLAUGHLIN MICHAEL
Abstract: Method and apparatus for measuring the strength of a high frequency signal. The strength of a high frequency signal is read-off two or more times at predetermined intervals and the read-off value which is the largest is selected. The selected signal strength is a reasonably precise measurement of the signal strength, as the actual average value for the strength of a signal which is affected by Rayleigh fading is close to the peak value of the signal strength. The method and apparatus according to the invention are particularly suited for use in a scanning receiver in a base station in a cellular radio communication system. The scanning receiver comprises an antenna selector 102 for selection of one sector antenna from among several, a high frequency receiver 104 which can be tuned to several different signal frequencies, an analogue-digital converter 106 which converts the read-off signal strengths to a binary data signal and a microprocessor 114 with peripheral equipment 108, 110, 112, 116, 118, 120 for controlling the operation of the antenna selector 102, the receiver 104 and the analogue-digital converter.
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公开(公告)号：GB2342832B
公开(公告)日：2001-03-21
申请号：GB9917920
申请日：1999-08-02
Applicant: MOTOROLA INC
Inventor： LI TOM HONG , MCLAUGHLIN MICHAEL
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