Patent ID: 7042377

Claim:
An analog-to-digital sigma-delta modulator for converting analog input signals to digital output signals comprising feedback path means for producing analog feedback signals that are a function of said digital output signals, integrator means for integrating analog difference signals that are a difference function of said input signal and said analog feedback signals, and a quantizer responsive to the signals integrated by said integrator means for producing said digital output signals at clock intervals, said integrator means including ‘N’ integrator stages, where ‘N’ is at least two, said input signal being applied to a first one of said integrator stages, said feedback path means including ‘N’ feedback stages for feeding back said feedback signals at respective integrator stages of said integrator means, and said feedback path means including finite impulse response filter means, each of said ‘N’ feedback stages comprising finite impulse response filter means, each of said finite impulse response filter means being of order ‘M’, where ‘M’ is at least two, and at least the filter of the feedback stage that feeds back to said first integrator stage being a low pass filter.