An alternative approach to the realization of network transfer functions: The N-path filter

A particular time-varying network consisting of several parallel transmission paths, each containing input and output modulators, is described and analyzed. It is shown that, under certain conditions, the network may be characterized by a transfer function. A particular form of this transfer function yields periodic filtering characteristics over a limited frequency band without employing distributed elements. Techniques are also presented for realizing highly selective band-pass filters without the use of magnetic elements. Some practical applications are discussed in detail and experimental verification is presented.