Title :
High-selectivity SC filters with continuous digital Q-factor programmability
Author :
Ausin, J.L. ; Pérez-Aloe, R. ; Duque-Carrillo, J.F. ; Torelli, G. ; Sánchez-Sinencio, E.
Author_Institution :
Dept. of Electron. & Electr. Eng, Univ. de Extremadura, Badajoz, Spain
Abstract :
This paper describes a quality factor (Q) programming technique for high-Q switched-capacitor (SC) filters. Although the selectivity is digitally programmed by varying the effective sampling frequency of an SC branch, without modifying any capacitor value, a continuous Q-factor tunability is obtained, avoiding, in principle, the inherent quantization error associated to any traditional programming approach. Automatic Q-factor tuning is performed, using a scheme based on an amplitude-locking loop approach. Experimental results obtained from a 0.8-μm CMOS second-order SC bandpass filter are given.
Keywords :
CMOS analogue integrated circuits; Q-factor; band-pass filters; programmable filters; switched capacitor filters; 0.8 micron; CMOS second-order filter; amplitude locking loop; automatic Q-factor tuning; continuous digital Q-factor programmability; effective sampling frequency variation; high-Q switched-capacitor filters; high-selectivity SC filters; quality factor programming technique; quantization error; Band pass filters; Capacitance; Capacitors; Clocks; Digital filters; Frequency; Q factor; Quantization; Sampling methods; Signal resolution;
Conference_Titel :
Circuits and Systems, 2002. ISCAS 2002. IEEE International Symposium on
Print_ISBN :
0-7803-7448-7
DOI :
10.1109/ISCAS.2002.1010535
