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    3.
    发明专利
    未知

    公开(公告)号：DK174787B1

    公开(公告)日：2003-11-10

    申请号：DK427085

    申请日：1985-09-20

    Applicant: INTERDIGITAL TECH CORP

    Inventor： PANETH ERICH ,  CRITCHLOW DAVID N ,  YEHUSHUA MOSHE

    IPC: H03D7/00 ,  A63B31/00 ,  H04L27/18 ,  H04L27/20 ,  H04L27/22 ,  H04L27/227

    Abstract: A modulator for a modem, said modulator being adapted to convert a bit stream, wherein each given number of successive bits defines a symbol, into a phase modulated intermediate frequency (IF) signal, the symbols in the modulator section being phase modulated DPSK conversion. The phase modulated symbols are then digitally filtered to provide a filtered signal comprising time shared, digital in-phase and quadrature phase components that, when converted into an analog signal, provides a modulation signal of a frequency that is centered about a predetermined frequency and deviates therefrom in accordance with the value of the phase modulated symbol. The filtered signal, after being converted to an analog signal is then filtered and passed to a mixer for up conversion to an IF signal.

    SUBSCRIBER UNIT FOR WIRELESS DIGITAL TELEPHONE SYSTEM
    5.
    发明专利
    SUBSCRIBER UNIT FOR WIRELESS DIGITAL TELEPHONE SYSTEM 未知

    公开(公告)号：CA1338743C

    公开(公告)日：1996-11-26

    申请号：CA608566

    申请日：1989-08-16

    Applicant: INTERDIGITAL TECH CORP

    Inventor： CRITCHLOW DAVID N ,  PANETH ERICH ,  YEHUSHUA MOSHE

    IPC: H04B1/40 ,  H04B7/26 ,  H04L5/22 ,  H04L27/18 ,  H04M1/00 ,  H04Q7/32

    Abstract: A digital wireless subscriber telephone unit for wireless connection with a base station. The subscriber unit has a baseband processor which is coupled to storage means for the baseband functions. The baseband processor is direct access coupled to a modem processor whereby the two processors may communicate with each other. The modem processor generally acts as the master in the system, although lock-out means may be used in certain circumstances. The signal from the modem processor is converted to an analog signal, which is subjected to deglitching, and the deglitched signal is then upconverted and filtered to form an IF signal which is thereafter amplified. The amplified IF signal is combined with a signal generated by a synthesizer to provide an RF signal. On the basis of certain signals received from the base station, the baseband processor produces initiating signals which determine whether the subscriber unit will be in the transmit mode or the receive mode. In intervals between actuation of the system, a training mode is used wherein a known signal from the modem processor is compared with looped-back signal to produce correction constants to compensate for undesirable variations in the IF, these constants being stored for use in correcting actual received signals. During demodulation, the modulated digital signals are fed to the modem processor in the form of time multiplexed I and Q samples and are demultiplexed. The demultiplexed I and Q samples are fed to an equalizer and frequency correction circuit for minimization of errors and for production of a frequency correction signal which is used to correct any errors in the timing of the system and in the output of the synthesizer.

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