Network Functions of Quadrature N-Path Filters

The general exact time-varying network functions of N-path filters, called quadrature N-path filters (QNF), are obtained in integral and series forms. It is shown that a subclass of the QNF has characteristics similar to previously treated sampled N-path filters (SNF) and that for a given number of paths N, the allowable input signal frequency bandwidth of the QNF is twice as large as that of the SNF. Thus the mimimum N for the QNF is two instead of the three required for the SNF. It is also shown that the well-known networks used in Weaver\´s "third method" of generating and detecting single-sideband signals correspond to the quadrature two-path filters.