N × M-path filters: analysis and implementation

Conventional N-path filters are often implemented by using a number of switches and internal low-pass filters that are used in zero-IF receivers. In this paper, by using M-path filters instead of internal low-pass filters, N × M-path structure is obtained in three states: single-ended input to single-ended output, single-ended input to differential output and harmonic rejection . These structures can be used in low-IF receivers and also to tune the desired filtering frequency more precisely. Analysis and implementation of each structure is also provided.