Patent ID: 7015843

Claim:
A sigma-delta converter for converting a digital input signal into an analog output signal with noise suppression within a useful band, comprising: a principal path including at least one principal path sigma-delta modulator having a transmission function including a filter and having an output producing a digital output signal, and at least one principal path digital-to-analog converter respectively coupled to the output of the at least one principal path sigma-delta modulator; at least one parallel path connected in parallel with the principal path, each parallel path including at least one parallel path sigma-delta modulator receiving a differential signal filtered to exclude at least noise components outside the useful band and obtained from the digital output signal of the principal path sigma-delta modulator and the input signal after spectral shaping by the filter according to the transmission function of the sigma-delta modulator in the principal path, and having an output, and a parallel path digital-to-analog converter coupled to the output of the at least one parallel path sigma-delta modulator; and an analog signal totaler, coupled to the principal path and the at least one parallel path, producing an analog output signal of the sigma-delta converter from analog output signals of the principal and parallel paths.