Control of injection locking of a millimeter wave oscillator with AFC

Application of automatic frequency control (AFC) to regulate the spectrum of an injection-driven oscillator is reported. This technique can eliminate noisy asymmetrical multiple sidebands. It is shown that the AFC loop changes the spectrmn to those lines of simple mixing, viz., stable local oscillator, incident signal, and image frequency. The change is reversible, merely by connecting and disconnecting the AFC.