An improved differential N-path filter with sampling computation for increased stopband rejection ability

An implementation of a differential N-path filter with sampling computation design method is proposed. It offers the ability to eliminate the harmonic passbands of the clock frequency. On top of that, the proposed method enables the scale of the whole filter to be reduced by approximately half for easier realization. By using the proposed method, previous work involving a 8-path filter can be reduced to 5-path, which reduces the scale of the circuit and at the same time has the performance of a 10-path filter if designed with the method proposed by previous work. An example of differential 7-path filter using the same proposed design method is also stated in comparison of the differential 5-path filter. The differential 7-path filter offers the ability to eliminate all the passbands below 10 times the clock frequency with a tradeoff of a slight increase of circuit scale.