COFDM demodulator with an optimal FFT analysis window positioning

A COFDM demodulator intended to receive a signal received from a transmit channel, comprising:

• a circuit of fast Fourier transform of the received signal in a window corresponding to a symbol, each symbol comprising several carriers modulated in phase and/or in amplitude, some of which are pilots, and being adjacent to a guard interval reproducing part of the symbol;
• a circuit for providing a set of estimated values of the module of the pulse response from the pilots;
• a circuit for determining coefficients, each coefficient being obtained from the product of said set and of a filtering function for a determined relative position of the filtering function with respect to said set;
• a circuit for determining the maximum coefficient and the corresponding relative position;
• and
• a circuit for positioning said window according to said relative position corresponding to the maximum coefficient,
• the filtering function comprising a central portion of constant amplitude and of duration equal to the duration of the guard interval, surrounded with non-zero decreasing sides.