1. In a temperature compensated crystal oscillator (TCXO) circuit that includes an oscillator for generating a signal whose frequency changes responsive to a temperature compensation signal, the oscillator including a piezoelectric device whose frequency characteristics change responsive to changes in ambient temperature, a method for modifying the temperature compensation signal to offset a trim effect caused by a variation in load capacitance of the piezoelectric device, the method comprising the steps of: A) providing a temperature compensation signal whose amplitude changes responsive to changes in the ambient temperature; B) providing a plurality of discrete frequency adjust values; and C) scaling the temperature compensation signal, responsive to the plurality of discrete frequency adjust values to produce a modified temperature compensation signal that offsets the trim effect.