a precision sigma - delta analog - to - digital converter disposed to operate at a sampling rate giving rise to a relatively low oversampling ratio is disclosed herein . the high - order sigma - delta analog - to - digital converter of the present invention is operative to convert an analog input signal to a digital output sequence . the inventive converter includes a first integrating network for generating a first sampled analog signal in response to the analog input signal . a second integrating network generates a second sampled analog signal in response to the first sampled analog signal . a third integrating network generates a third sampled analog signal in response to the second sampled analog signal . the sigma - delta converter of the present invention further includes an internal quantizer for generating the digital output sequence in response to the third sampled analog signal . a feedback network supplies the first , second and integrating networks with an analog feedback signal generated in response to the digital output sequence .