Programmable signal generator with phase locked loop - has two integral multiple reference frequencies mixed with output of VCO

摘要

The programmable signal generator, with phase locked loop, consists essentially of two or more series coupled mixers or phase discriminators that mix the vco output with two or more reference signals (each an integral multiple of a basic frequency) to form the error signal for applying to the vco's control input. In its simplest form the generator has a first mixer (E1) to mix the vco output with a reference signal (mP) whose frequency is an integral multiple of a first reference (P). The first mixer's output is LP filtered (FL) and mixed with the first reference. The second mixer's (E2) output controls the vco frequency. Other variations include switched references to the same mixer extra filters and more mixers.