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    SOFT DECISION DECODING WITH CHANNEL EQUALIZATION
    24.
    发明专利
    SOFT DECISION DECODING WITH CHANNEL EQUALIZATION 未知

    公开(公告)号：CA2066270C

    公开(公告)日：1995-03-28

    申请号：CA2066270

    申请日：1990-09-24

    Applicant: MOTOROLA INC

    Inventor： LABEDZ GERALD P ,  BORTH DAVID E ,  RASKY PHILLIP D

    IPC: H04L25/08 ,  H04L25/03 ,  H04L27/00 ,  H04L27/01 ,  H04B3/06

    Abstract: In a communications network having time-dispersed signals, there is provided a mechanism for soft decision decoding. It comprises: radio reception of a time-dispersed signal, at least partly equalizing those time-dispersal effects, recovering information contained in the signal, multiplying with that recovered information the absolute value of that at-least-partly-equalized signal (scaled by a number derived from channel conditions over a time during which at least part of the information to be recovered is distributed), and error-correcting the multiplied information by a Viterbi algorithm channel decoding scheme of error correction. Accordingly, soft decision information is generated from whithin the equalization process itself.

    ALL-DIGITAL QUADRATURE MODULATOR
    25.
    发明专利
    ALL-DIGITAL QUADRATURE MODULATOR 未知

    公开(公告)号：CA2003938C

    公开(公告)日：1994-05-03

    申请号：CA2003938

    申请日：1989-11-27

    Applicant: MOTOROLA INC

    Inventor： BORTH DAVID E

    IPC: H04L27/20 ,  H04B1/04 ,  H04L27/12

    Abstract: A CPFSK quadrature modulator (300) is disclosed utilizing an all-digital implementation. The serial data input signal (201) is formatted into parallel overlapping bits using a shift register (202), an up/down counter (206), and an interpolation counter (204), and applied as address lines to in-phase and quadrature-phase memories (208, 210). A multiple of the bit clock is used to address carrier generation ROMs (216, 218). The carrier signal is then modulated by the in-phase and quadrature-phase data signals (212, 214, 222), converted to an analog signal by a D/A converter (250), and low pass filtered (254) to generate the analog output signal (255). A single ROM (440) is utilized to implement all the look-up tables, multipliers, and adder. The all-digital implementation allows for precise control of the modulation index to h=0.5 ? 0.05 percent over time, temperature, power levels, etc.

    DIGITAL AUTOMATIC FREQUENCY CONTROL OF PURE SINE WAVES
    29.
    发明专利
    DIGITAL AUTOMATIC FREQUENCY CONTROL OF PURE SINE WAVES 未知

    公开(公告)号：CA2003688C

    公开(公告)日：1993-10-05

    申请号：CA2003688

    申请日：1989-11-23

    Applicant: MOTOROLA INC

    Inventor： BORTH DAVID E ,  KEPLER JAMES F M

    IPC: H03L7/095 ,  H03J7/02 ,  H03L7/08 ,  H03L7/087 ,  H03L7/085

    Abstract: There is provided a method of and apparatus for Automatic Frequency Control (AFC) of pure sine waves (PSW). It comprises discriminating to detect frequency differences between a received pure sine wave and a reference frequency, integrating the frequency differences to average the differences, and adjusting the reference frequency to eliminate the frequency difference. It is further characterized by digitizing, in quadrature, the received pure sine wave, mixing the received pure sine wave with a complex sinusoid to translate the pure sine wave to baseband, quadrature filtering the mixed sine wave, cross-product discriminating to detect frequency differences between a received pure sine wave and a reference frequency, integrating the frequency differences to average the differences, selectively calculating the mean/variance between the pure sine wave and the reference frequency, and adjusting the reference frequency of a Voltage Controlled Oscillator to eliminate the frequency difference.

    METHOD AND SYSTEM FOR CALCULATING CHANNEL GAIN
    30.
    发明专利
    METHOD AND SYSTEM FOR CALCULATING CHANNEL GAIN 未知

    公开(公告)号：GB2263048A

    公开(公告)日：1993-07-07

    申请号：GB9303638

    申请日：1992-05-07

    Applicant: MOTOROLA INC

    Inventor： MUELLER BRUCE D ,  BAUM KEVIN L ,  BORTH DAVID E ,  RASKY PHILIP D ,  WINTER ERIC H

    IPC: H04B3/04 ,  H04B7/00 ,  H04B7/005 ,  H04B7/08 ,  H04L1/02 ,  H04L25/06 ,  H04L27/01 ,  H04L27/22

    Abstract: The system determines at least one property of a communication channel which connects a transmitter and a receiver. The system includes a device (134) for generating values of at least sampled sections of a received signal which is received by the receiver after transmission over the channel. The variance of the generated values is then determined (146). Another device (154) quantises the values of the received signal to provide a quantised value. An error signal is then provided (162) in response to the difference between the values of the sample, received signal and the quantised values. A device (170) calculates the variance of the error signal. The channel amplification property of the communication channel is then calculated (178) in response to the variance of the generated values and the error signal.

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