A signal generation circuit includes a crystal oscillator for generating an oscillatory signal and a temperature compensation circuit coupled to the oscillator for controlling the capacitance loading of the crystal in the oscillator. The temperature compensation circuit includes a temperature sensing device and operates to develop a first capacitance in a first temperature range, a second capacitance which varies at a ertain rate with the variation in temperature in a second temperature range, and a third capacitance which varies at a different rate with the variation in temperature in a third temperature range.