Wide range frequency synthesizers with improved dynamic performance

In a simple phase lock loop type of frequency synthesizer the closed-loop dynamic performance dictates the settling time after a frequency step, the close-in noise spectrum, the achievable cancellation of microphony in the output oscillator, and the flatness of the frequency modulation characteristic. The dynamic performance is controlled mainly by the proportional and not the integral part of the loop gain. Several techniques are described for ensuring a constant loop gain and hence good overall performance for the synthesizer over a wide frequency range of operation.