Abstract: A differential, interpolating, switched capacitor filter and method of operation in which non-interpolating stages of the filter are clocked at a first frequency and a subsequent interpolating stage of the filter is operated at double the first frequency to achieve improved smoothing of the output wave form. The switched capacitors in the interpolating stage which feed forward a differential input from a prior stage to an input to the interpolating stage, and which feed a differential output from the interpolating stage back to an input thereto are paired and switches are provided for the added capacitors so that all of these capacitors are switched. Capacitors which are directly coupled to feed forward a differential input from a prior stage to the interpolating stage are also paired, but only the added capacitor is switched.