Patent ID: 8514116

Claim:
A method for improving resolution and for correcting distortions for a sigma-delta modulator, the modulator converting an analog input signal e(t) into an output digital signal s(t) sampled at a frequency f e and coded on N B =N MSB +N LSB bits, of which N MSB are high-order bits MSB and N LSB are low-order bits LSB, the N MSB MSB bits being fed back in the modulator, the signal fed back after digital-analog conversion of the N MSB MSB bits being re-sampled at the frequency f e to generate a second output digital signal s′(t) represented on N MSB bits, the method comprising applying, at the output of the modulator: a first processing which carries out a demodulation by a frequency f 0 and a decimation of factor N independently on the signals s(t) and s′(t); a second processing for improving the resolution of a result of the first processing; and a third processing for correcting distortions of a result of the second processing, wherein the second and the third processings comprise filtering operations having impulse responses which are derived from an estimation ξ 0 (t) of an open-loop analog response ξ(t) of the modulator based on measurements of an open-loop impulse response ξ k (t), said measurements having been carried out on output from the first processing.