Hybrid filter employing digital techniques and analog components and amti radar employing same

摘要

A filter employing the principles of digital filters representative of Z-transform solution of mth-order difference equations is implemented using analog components; arithmetic units are realized by resistive networks employed with operational amplifiers, and memory elements are realized by the use of switched capacitors. A particular embodiment comprises a cascade implementation of a Cauer or elliptic filter applied to range-gated clutter attenuation in an airborne moving target indicator (AMTI) radar; time sharing of arithmetic units among range bins, multiplexing of slow filters for achievement of faster overall system response, and electronically variable filter characteristics (through electronic component selection) are disclosed.