Pulse or digital communications – Receivers – Angle modulation
Patent
1993-04-02
1995-08-01
Chin, Stephen
Pulse or digital communications
Receivers
Angle modulation
329304, 329306, 375327, 375333, 375344, H03D 322, H04L 2722
Patent
active
054385946
ABSTRACT:
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.
REFERENCES:
patent: 3983499 (1976-09-01), Tan
patent: 4344178 (1982-08-01), Waters
patent: 5179578 (1993-01-01), Ishizu
40th IEEE Vehicular Technology Conference, 6-9 May, 1990, Orlando, US; IEEE, New York, US, 1990; pp. 687-694, Goode, et al.; "A comparison of limiter-discriminator, delay and coherent detection of pi/4 QPSK".
Chin Stephen
Luther William
Societe Anonyme dite Alcatel Telspace
LandOfFree
Device for demodulating digital signals modulated by an alternat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for demodulating digital signals modulated by an alternat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for demodulating digital signals modulated by an alternat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-738706