CRYSTAL FILTER CIRCUIT WITH SHARPLY DEFINED PASSBAND EDGE

摘要

A crystal filter is disclosed wherein compensation for passband edge rounding due to inherent crystal resistance is afforded using an attenuation equalizer arrangement providing an impedance which caries as a function of frequency such that its magnitude is of a minimum value in the vicinity of the passband edge to be sharply defined. The attenuation equalizer includes a resistive T-network and a crystal resonator having a series resonant frequency approximately equal to the cutoff frequency at the aforementioned passband edge.