NEW LINEARLY TUNABLE CMOS-COMPATIBLE OTA-C OSCILLATORS WITH NONINTERACTING CONTROLS

Operational transconductance amplifier capacitor (OTA-C) sinusoidal oscillators have attracted considerable attention recently because they offer several advantages over conventional op-amp-based oscillators, as well as because in conjunction with CMOS OTAs, they lead to the evolution of fully integrated oscillators in CMOS technology. The purpose of this paper is two-fold: first to present three new canonic (employing only two capacitors) four-OTA-C sinusoidal oscillator circuits possessing the capability of providing independent lineal control of the frequency of oscillation, and then to describe an approach to converting these structures into CMOS VCOs, which requires a reduced number of components as compared to the CMOS OTA-based approaches used earlier. The validity of the proposed formulations has been confirmed by SPICE simulation results.