Device for the reception of digital data time frequency interlacing, notably for radio broadcasting at high bit rate towards mobile receivers with nyquist temporal window

Claim 1

A receiver of a digital source signal, comprising digital symbols, transmitted using a plurality of simultaneously broadcast orthogonal frequency carriers, the receiver comprising: means for forming a digital baseband signal from a received signal including: a local oscillator for transposing the received signal into a demodulated signal, baseband filtering means for filtering the demodulated signal to form an analog baseband signal, and analog-digital conversion means for digitizing the analog baseband signal to form the digital baseband signal consisting of successive temporal samples; a temporal windowing module coupled to said analog-digital conversion means for forming a series of successive samples the temporal windowing module including means for weighting said digital baseband signal, the weighting being carried out according to a Nyquist temporal window with non-zero roll-off having a first ascending flank with duration t r , a constant portion with duration t s -t r , where t s and t r are predetermined time periods, and a second descending flank symmetric to the first ascending flank, the Nyquist temporal window being defined by a mathematical function f simultaneously meeting the following conditions, x being a real variable representing time: f(-t.sub.r /2+x)+f(-t.sub.r /2-x)=1 for 0≦x≦t.sub.r /2; f(t.sub.s -t.sub.r /2+x)+f(t.sub.s -t.sub.r /2-x)=1 for 0≦x≦t.sub.r /2; and f(x)=1 for 0≦x≦t.sub.s -t .sub.r ; and transformation means for mathematically transforming said series of successive samples into a set of frequential coefficients thus forming a transformed signal.