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CMOS digitally programmable quadrature oscillators
Author(s) -
Alzaher Hussain A.
Publication year - 2008
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.479
Subject(s) - cmos , electronic engineering , transconductance , interfacing , operational transconductance amplifier , engineering , amplifier , electrical engineering , capacitor , analog signal processing , operational amplifier , chip , voltage , computer science , transistor , signal processing , digital signal processing , computer hardware
CMOS digitally programmable quadrature oscillators based on digitally controlled current followers and voltage followers are proposed. The proposed designs provide the advantage of programmability similar to the operational transconductance amplifier‐based oscillators while offering improved linearity. In mixed analog/digital systems, the digital tuning feature allows direct interfacing with the digital signal processing part. Novel realizations that provide both voltage‐mode and current‐mode quadrature sinusoidal signals are presented. Employing only grounded capacitors the designs achieve independent control of the frequency and condition of oscillation that can be tuned digitally. Experimental results obtained from a 0.35 µm CMOS chip fabricated using standard CMOS process are given. Copyright © 2008 John Wiley & Sons, Ltd.