SIXTEEN-POSITION QUADRATURE-AMPLITUDE KEYING CARRIER FREQUENCY RESTORATION DEVICE Russian patent published in 2005 - IPC

FIELD: radio engineering.

SUBSTANCE: sixteen-position quadrature-amplitude keying (QAK-16) signal is mixed with noise at the input. After it low-frequency signals at outputs of phase detectors (PD) are processed in comparators, adders and multipliers and control voltage if formed for voltage controlled generator (VCG). Low-frequency signals at outputs of PD are processed in count pulse forming units (CPFU) and pseudo-noise signals are formed at outputs of first adders in each CFPU. Pseudo-noise signal is commutated through commutator of each CFPU to input of second adder of each CPFU with output of that amplifier which corresponds to extremely high operation value of Rinput=Rmax. Count pulses are formed at output of any CPFU. Current number of count pulses is counted during specific number of clock intervals and Rinput is estimated. Correspondingly to value of input estimation the commutator is controlled, which commutator directs control voltage for controlled voltage generator (VCG) to input of CVG through corresponding filter (which actually corresponds to estimation of Rinput). The innovation described is that commutators are subject to control in each CFPU which CFPU direct pseudo-noise signal for subsequent processing through corresponding amplifiers correspondingly to estimated value of Rinput but value of Rmax. In this case, due to commutation of optimal pseudo-noise signal received for Rinput range of amplifier, the unit optimally tunes to signal in each CPFU that results in higher precision of measurement.

EFFECT: increased noise immunity of restoration of carrier frequency of signal of QAK-16.

2 dwg, 2 tbl