Low pass and band pass high quality coilless filters - for integrated circuits use gyrators and capacitors

摘要

A number of circuits is presented in which gyrators are used to replace inductances, together with suitable capacitances, arranged in various N-path configurations. The capacitances are switched into circuit at sampled times by suitable clocked switches to give the low pass or band pass characteristics required. Three configurations of elements are shown. The first is a low or band pass filter consisting of a gyrator with switched capacitive networks at input and output. The second is a more complex arrangement with the gyrator linking a branch network of switched capacitances to the main circuit. The third consists of several systems of switched capacitances linked with two gyrators.