Title :
Accurate automatic tuning circuit for bipolar integrated filters
Author :
De Heij, Wim J A ; Hoen, Klaas ; Seevinck, Evert
Author_Institution :
Dept of Electr. Eng., Twente Univ., Enschede, Netherlands
Abstract :
An accurate automatic tuning circuit for tuning the cutoff frequency and Q-factor of high-frequency bipolar filters is presented. The circuit is based on a voltage controlled quadrature oscillator (VCO). The frequency and the RMS (root mean square) amplitude of the oscillator output signal are locked to the frequency and the RMS amplitude of a reference signal, respectively. Special attention is paid to the actual Q-factor in the oscillator. Experimental results for a breadboard circuit operating from 136 to 317 kHz are presented
Keywords :
Q-factor; active filters; bipolar integrated circuits; linear integrated circuits; tuning; 136 to 317 kHz; Q-factor; RMS amplitude; VCO; automatic tuning circuit; bipolar integrated filters; cutoff frequency; high-frequency; integrator circuit; monolithic IC; reference signal; voltage controlled quadrature oscillator; Circuit optimization; Cutoff frequency; Feedback circuits; Filters; Q factor; Resistors; Transconductance; Transconductors; Tunable circuits and devices; Voltage-controlled oscillators;
Conference_Titel :
Circuits and Systems, 1990., IEEE International Symposium on
Conference_Location :
New Orleans, LA
DOI :
10.1109/ISCAS.1990.112327
