| 摘要 |
A device for demodulating a signal modulated on two axes in phase quadrature using a pi /4-QPSK type digital modulation technique employing alternately two phase-shifted constellations. The device includes: a voltage-controlled oscillator (28) supplying a local signal substantially at the carrier frequency; a demodulator means using the local signal and supplying, after filtering (30, 31), the phase component P and quadrature component Q of the demodulated received signal; a phase controller (32) producing a control signal (39) for controlling the oscillator (28) and including a phase estimator (33) producing a phase estimation signal E (35) involved in control of the oscillator (28), the phase estimation signal being derived from the phase component P and quadrature component Q of the demodulated received signal. The phase controller has an inverter (34) for alternately inverting the polarity of the phase estimation signal E (35) at the rate at which the constellations alternate supplying the control signal (39) for controlling the oscillator (28) after filtering (29) in the loop.
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