Structure of a coherent dual channel QPSK transceiver using pilot symbols in a code division multiple access system

  • US 6,219,374 B1
  • Filed: 07/14/1998
  • Issued: 04/17/2001
  • Est. Priority Date: 11/25/1997
  • Status: Expired due to Term
First Claim
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1. A coherent dual-channel Quadrature Phase Shift Keying (QPSK) transceiver device using pilot symbols in a code division multiple access system, comprising:

  • a serial-to-parallel converter for dividing a communication signal which comprises data bits into an in-phase channel signal and a quadrature channel signal;

    a first pilot symbol adder for periodically inserting pilot symbols into said in-phase channel signal;

    a second pilot symbol adder for periodically inserting said pilot symbols into said quadrature channel signals;

    first and second mixers for spreading said in-phase channel signals and said quadrature channel signals into which said pilot symbols are periodically inserted using different Walsh codes;

    third and fourth mixers for spreading said in-phase channel signals and said quadrature channel signals which have been spread by said different Walsh codes using different PN codes;

    first and second pulse-shaping filters for pulse-shaping outputs of said third and fourth mixers, respectively;

    fifth and sixth mixers for frequency-modulating said pulse-shaped in-phase channel signals and quadrature channel signals into carriers cos(2π

    f0t+θ

    k) and sin(2π

    f0t+θ

    k), respectively; and

    a high-power amplifier for amplifying outputs of said fifth and sixth mixers and transmitting resulting transmit signals to an antenna.

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