Injection-lock bandwidth extension by control modulation and current 'hump' slope detection

A scheme used to extend the injection-locking bandwidth of an electronically tuned microwave solid-state source and to cancel the residual phase error is described. To slope-detect a control modulation, which is then used to eliminate the difference between the free-running frequency and the injected frequency, the power-supply current hump phenomenon is used. It is shown that the scheme is used with excellent results to lock a 35 GHz source and that the lowest injected power usable is -55 dBc.