DEMODULATOR FOR SIGNALS OF SIXTEEN-POSITION QUADRATURE AMPLITUDE MODULATION Russian patent published in 2007 - IPC H04L27/22 

FIELD: radio engineering, possible use for demodulation of signals of sixteen-position quadrature amplitude modulation.

SUBSTANCE: demodulator of signals of sixteen-position quadrature amplitude modulation (dwg.1) contains phase detectors 1,2, low frequency filters 3,4,54, comparators 5-14,38-41, AND elements 15,16,44,45,56, phase shifter 17 for 90°, block 18 for restoration of carrier, OR elements 19-23,28,29,42,43,53, counters 24-26,30-32,46-48, decoder 27, comparison block 33,49, reverse counters 34,50, digital-analog converter 35,51, controllable amplifiers 36,37,52, threshold block 55. Count interval is selected equal to n=(10÷100)·16, while beginning of operation of precise loop is only permitted after achievement of synchronism in crude loop, resulting in exclusion of possible cases of erratic operation of second level adjustment loop, providing for achievement of maximally possible resistance of device to interference.

EFFECT: increased resistance of signals of sixteen-position quadrature amplitude modulation to interference.

7 dwg, 2 tbl