Oscillation amplitude control for the bandpass-type sinusoidal oscillator over a wide frequency range

A circuit design is presented to control the amplitude of the bandpass-type sinusoidal oscillator and is implemented with a current conveyor. High-speed comparators are employed to detect the oscillation amplitude. A negative feedback technique with digital hardware is applied for amplitude control. The designed circuit can correct the pair of characteristic roots of the overall system automatically to the imaginary axis of the complex frequency plane. No low-pass filter is needed, and thus the designed circuit can be applied validly over a wide oscillation frequency range. Oscillation frequencies ranging from 7 Hz to 1 MHz are tested with the designed circuit. The experimental results demonstrate the static characteristics and dynamic responses of the overall system.