Abstract: Disclosed apparatus compensates for the parabolic temperature induced frequency drift characteristic of a surface acoustic wave tuned oscillator. The apparatus includes a pair of varactor diodes and a temperature sensitive voltage supply. The diodes are series connected and coupled in circuit with the oscillator to affect the frequency thereof. The voltage supply connects to the common connection of the diodes, for producing control voltages thereat.Each varactor diode is chosen to have a .delta. > 1; and the control voltage varies linearly with temperature. This results in a varactor diode capacitance versus temperature characteristic which is a continuous, true parabolic function providing precise compensation for the thermal drift of oscillator frequency.