DEVICE FOR THE COHERENT DEMODULATION OF TIME-FREQUENCY INTERLACED DIGITAL DATA, WITH ESTIMATION OF THE FREQUENCY RESPONSE OF THE TRANSMISSION CHANNEL AND THRESHOLD, AND CORRESPONDING TRANSMITTER

摘要

A coherent demodulation device, for the demodulation of a digital signalof the type constituted by digital elements distributed in the time-frequencyspaceand transmitted in the form of symbols constituted by a multiplex of Northogonalcarrier frequencies modulated by a set of the digital elements and broadcastsimultaneously, the digital signal comprising reference elements, having avalue anda position, in the time-frequency space, that are known to the demodulationdevice,comprising means for the estimation, by Fourier transform, of the frequencyresponse of the transmission channel at any instant, carrying out thetransformationof the received samples, corresponding to reference elements, from thefrequencydomain to the temporal domain, the multiplication in the temporal domain ofthetransformed samples by a rectangular temporal window (f n) and the reversetransformation, after the multiplication, of the obtained samples from thetemporaldomain into the frequency domain, the estimation means comprising means forthethresholding of the samples in the temporal domain, providing for thesystematicelimination of the samples below a certain threshold.