Frequency agile microwave signal generator

摘要

A frequency synthesized, microwave signal generator (50) is disclosed that provides multiple channel frequency selection capability with rapid channel change time and low levels of spurious signals and noise. The generator (50) uses a microwave harmonic phase locked loop (82) to lock a microwave VCO (68) to a programmable harmonic of a VHF reference crystal oscillator (60) to provide coarse frequency control in steps equal to that reference frequency. The phase lock loop (82) includes an offset mixer (74) for injecting an offset signal frequency to achieve fine frequency control. A harmonic detection and counting scheme is used to rapidly sweep the harmonic loop (82) and to obtain phase lock at the desired harmonic (Figure 1).