A feedback coder, which employs simple CMOS push/pull amplifiers as gain elements, along with a bistable circuit, in its preferred embodiment takes the form of a second-order delta-sigma modulator. The output of the modulator is converted into pulse code modulated words by a finite impluse response filter which incorporates a partial coefficient generator utilizing simplified logic. The generator output is provided to an accumulator in which the stage operate at reduced speed. A simple multiplexer generates a serial output. The entire converter can be integrated on a semiconductor chip of relatively small area.