Voltage controlled crystal oscillator

Claim 1

In apparatus wherein a frequencymodulated continuous wave signal is produced, the characteristics of the modulation being controllable, the combination of: a. a modulator network having a nonlinear reactance over a frequency range f1 to f2 for producing a frequency modulation signal, such modulator network including: i. a varactor: ii. means for linearly varying the voltage across the varactor to change the reactance of such varactor over the frequency range f1 to f2; and b. an oscillator network, for generating a continuous wave signal, such network having a nonlinear reactance over the frequency range f1 to f2, the frequency of the continuous wave signal being moduLated over the frequency range f1 to f2 by the frequency modulated signal and being serially coupled to the varactor and including: i. a crystal; ii. an inductor disposed in parallel with the crystal; and, iii. a capacitor, disposed in parallel with the inductor, characterized in that the value of such capacitor is selected to shape the nonlinear reactance variation of the oscillator network over the frequency range f1 to f2 as a function of the nonlinear reactance variation of the modulator network to linearize the change in frequency of the continuous wave signal over the frequency range f1 to f2.