A current-tunable sinusoidal oscillator

A high-performance integrable current-tunable sinusoidal oscillator is proposed and experimentally investigated. A current-tunable bandpass filter is used as the frequency-determining network. Practical frequency-sweep ranges of approximately three orders of magnitude have been obtained. The maximum useful frequency of oscillation is in excess of 20 mHz, and the total harmonic distortions can be adjusted easily to be less than 0.5%. The measured temperature coefficient of the oscillation frequency is less than -30 p.p.m./°C. The circuit technique is simple enough for use in the construction of practical instrumental oscillators using only a few off-the-shelf integrated circuit packages.