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264 条记录 (耗时 0.014 秒)

    DIGITAL DOWN CONVERTER
    111.
    发明公开
    DIGITAL DOWN CONVERTER 审中-公开
    数字转换器的降压

    公开(公告)号：EP1425857A4

    公开(公告)日：2004-12-15

    申请号：EP02773190

    申请日：2002-08-14

    申请人： ADC BROADBAND ACCESS SYS INC

    发明人： UNGER DAVID ,  ENGELSE WILLEM ,  CORLEY WILLIAM ,  DAVIES DAVID ,  DORMITZER PAUL ,  ROBIDOUX RAYMOND

    IPC分类号： H03H17/00 ,  H03D7/00 ,  H03H17/06 ,  H03M3/00 ,  H03D3/00 ,  H03D7/16 ,  H03M3/02 ,  H03M7/00

    CPC分类号： H03H17/0685 ,  H03D7/00 ,  H03H17/0657 ,  H03H17/0664

    摘要： A digital down converter (100) is provided. The digital down converter (100) includes an input adapted (102) to receive an input signal (101), a mixer circuit (104) coupled to the input to down converter the input signal, and a decimation circuit (115) coupled to the mixer. The decimation circuit is adapted to decimate down converter signal by a factor selected based on a characteristic of the input signal. The digital down converter further includes a signal conditioning circuit (118), coupled to the output of the decimation circuit (115), that conditions the decimated signal, an interpolator (120) coupled to the decimation circuit, that increase the number of samples in the conditioned signal, and a second mixer circuit (126), coupled to the interpolator, the second mixer circuit adapted to modulate a carried with the conditioned signal.

    Time spread root nyquist filter
    117.
    发明公开
    Time spread root nyquist filter 失效
    运行不同的低通奈奎斯特

    公开(公告)号：EP0853382A3

    公开(公告)日：2000-05-10

    申请号：EP97122446.4

    申请日：1997-12-18

    申请人： YOZAN INC.

    发明人： Zhou, Xuping ,  Zhou, Changming ,  Shou, Guoliang

    IPC分类号： H03H17/00 ,  H04L25/03

    CPC分类号： H03H17/00 ,  H04L25/03834

    摘要： The present invention has the object to decrease the peak factor of a transmission signal and control impulse noise. The amplitude characteristics are identical to those of a normal root Nyquist filter, and the phase characteristics divide the passband into a plurality number, the root Nyquist filters having the phase corresponding to each bit value of PN codes with the length of the divided number are set on transmission and reception. Accordingly, even when the transmission signal has a high amplitude peak and a short connection time, the signal can be transmitted along the route by decreasing the peak to control the peak factor. Also, impulse noise can be restrained at reception.

    Apparatus for reproducing information recorded on optical disc
    118.
    发明公开
    Apparatus for reproducing information recorded on optical disc 失效
    一种用于记录在光盘上再现信息的

    公开(公告)号：EP0883124A3

    公开(公告)日：2000-05-03

    申请号：EP98109908.8

    申请日：1998-05-29

    申请人： PIONEER ELECTRONIC CORPORATION

    发明人： Hasebe, Seiichi

    IPC分类号： G11B19/247 ,  G11B19/28 ,  G11B20/10 ,  H03H11/12 ,  H03H17/00

    CPC分类号： G11B20/10037 ,  G11B20/10009 ,  G11B20/10296 ,  G11B20/1403 ,  G11B20/1866 ,  G11B20/22

    摘要： An apparatus for reproducing information recorded on an optical disc (1) which can favorably accomplish a time base correction for a read signal in a simple configuration. Also, the apparatus precisely removes jitter component produced when a read signal is converted to a predetermined encoded signal. The apparatus has a spindle motor (2) for rotating an optical disc (1), an optical pickup (3) for optically reading a recorded signal on the optical disc (1) to generate a read signal corresponding to the reproduced signal, and an A/D converter (6) for digitizing the read signal to reproduce an encoded signal. The apparatus is provided with a signal processing unit for removing low frequency noise components from the read signal without producing distortions in the direction of the time base of the read signal in the processing prior to outputting the encoded signal in the A/D converter.

    Fast response gain tracker for echo canceller
    119.
    发明公开
    Fast response gain tracker for echo canceller 失效
    快速响应增益调整的回声消除

    公开(公告)号：EP0766413A3

    公开(公告)日：1998-12-16

    申请号：EP96307073

    申请日：1996-09-27

    申请人： PARADYNE CORP

    发明人： BETTS WILLIAM LEWIS ,  ZURANSKI EDWARD SIGMUND

    IPC分类号： H03H17/00 ,  H04B3/23 ,  H04B7/015 ,  H04B7/26

    CPC分类号： H04B3/23

    摘要： A fast response gain tracker (610) operates to adjust the magnitude of an echo cancellation signal developed from an echo canceler. The fast response gain tracker (610) provides an adjusted echo cancellation signal that is subtracted from an echo-corrupted received signal to provide an echo-canceled signal. In particular, the fast response gain tracker (610) correlates the echo-canceled signal with the echo cancellation signal from the echo canceler. If the gain of the gain tracker is correct the echo is canceled and there is zero correlation between the echo-canceled signal and the echo cancellation signal. However, if the echo level changes then a residual echo component appears in the echo-canceled signal, which now becomes correlated with the echo cancellation signal. In response, the magnitude of the gain tracker automatically adjusts the gain of the echo cancellation signal to match the change in echo level and thereby subsequently eliminates the residual echo.

    Digital center line filter
    120.
    发明公开
    Digital center line filter 失效
    数字窄带滤波器

    公开(公告)号：EP0782259A3

    公开(公告)日：1998-06-03

    申请号：EP96309476

    申请日：1996-12-24

    申请人： HUGHES MISSILE SYSTEMS

    发明人： TARGOFF DONALD M

    IPC分类号： H03H17/00 ,  G01S7/285 ,  G01S13/88 ,  H03H17/02

    CPC分类号： H03H17/0286

    摘要： A center-line filter for a radar receiver (50) is a cascade of an analog filter (54A) and a digital filter (58A). The purpose of the filter cascade is to filter out all but a single line of a pulsed spectrum. The signal is passed through the analog filter, and then over-sampled by an analog-to-digital convertor (56A). A sharp cutoff FIR filter is used as the digital filter (58A) to eliminate the remaining undesired lines. since the analog filter already has the correct matched filter characteristic in the passband, the digital filter passband is deliberately wider and unsymmetrical. After digital filtering, the filter output is decimated by a decimation processor (60A) to provide a desired output data rate.