Title :
A radio-frequency tunable active filter
Author :
Taflove, Allen ; Brodwin, Morris E.
fDate :
4/1/1974 12:00:00 AM
Abstract :
A design approach for a tunable active filter of constant bandwidth and center-frequency gain is described. The approach is based on a feedback configuration with a complex zero pair in the feedback transfer function. Center frequency tuning is achieved with the variation of only one element, a potentiometer, which controls the feedback loop gain. A circuit realization using two commercial video amplifiers with RC embedding is presented. A tuning range of 25 percent at 5 MHz, with a nominal bandwidth of 90 kHz or 180 kHz, and a variation of center-frequency gain of less than /spl plusmn/1 dB over the tuning range, is obtained.
Keywords :
Active filters; Feedback; Tuning; active filters; feedback; tuning; Active filters; Bandwidth; Circuit optimization; Feedback; Frequency synthesizers; Poles and zeros; Radio frequency; Transfer functions; Tunable circuits and devices; Tuning;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.1974.1050465