Direct frequency modulation with CW Gunn and IMPATT oscillators

Demodulation of frequency-modulated signals has been carried out with frequency-locked CW Gunn and IMPATT oscillators. The process utilized the coupling between the bias current or voltage, respectively and the frequency deviation of the locked oscillator. A full characterization of this coupling is presented. An incremental model of the large-signal oscillator behavior is developed and shown to be in good agreement with the linear and nonlinear behavior of the demodulator.