摘要：There is introduced the fast digital noncoherentdemodulator of high-frequency differential quadrature phaseshift keyed signals that provides the minimum number ofarithmetic operations over the carrier frequency period. Thus,for the first time, for digital noncoherent demodulators theproblem is solved of increasing the speed of high-frequencysignal processing in common data transmission systems, forexample, in TETRA, PHS, SDMA, IEEE 802.11 and IEEE802.11b, ZigBee, etc. These and other data transmissionsystems operate at low power consumption, and this wouldneed to minimize FPGA resources required for theimplementation of the demodulation of high-frequency signals.This can be achieved by minimizing the appropriatecomputational costs in processing the signals. For this purposethe algorithm is presented that allows fast processing of thesignal samples with a subsequent decision on the receivedsymbol. The properties of the responses of the demodulatorand its frequency-selective properties are also demonstrated.There is studied the influence of phase and frequencymismatch on the performance of the demodulator. Theexpressions are found for the symbol-error probability for thecase when the information signal is distorted by band Gaussiannoise. It is proved that the considered algorithm providesoptimal signal extraction against broadband interferences anddemonstrates potential interference immunity in the presenceof Gaussian noises. It is established that the obtainedtheoretical results are confirmed by statistical simulation. Theimplementation of the proposed demodulation algorithm basedon the field programmable gate arrays makes it possible todesign highly efficient digital demodulators of high-frequencysignals while utilizing minimal FPGA resources.
关键词：Differential phase keying; digital demodulation; noncoherent processing; phase mismatch; frequency mismatch; interference immunity; bit-error probability
