Active filter circuit

摘要

An active filter circuit having emitter coupled first and second transmittors and emitter coupled third and fourth transistors, wherein the base and collector electrodes of the third transistor are connected to the base electrode of the first transistor, and the base and collector electrodes of the fourth transistor are connected to the base electrode of the second transistor with a reactance circuit connected to a collector electrode of the second transistor and an output terminal connected by the collector electrode of the second transistor such that the filter circuit has a small number of components and operates over a broad band.