Linear VCO with sine wave output

A sinusoidal oscillator whose frequency of oscillation bears a linear relation to the controlling voltage V_T is presented. The basic configuration involves a four-quadrant analog multiplier to adjust precisely the gain requirement for sustained oscillation with ultra-low-distortion operation. The oscillator results in a linear voltage-to-frequency converter with sine wave output. The circuit makes use of a scaled-resistance element R₁/K² to realize the oscillation frequency f in the form f=Kf₀, where the scaling parameter K is a linear function of V_T and f₀ is the unscaled frequency.