FREQUENCY MODULATED OUTPUT CLOCK FROM A DIGITAL FREQUENCY/PHASE LOCKED LOOP

摘要

A frequency modulated output of a Digital Locked Loop (DLL) is implemented with a Johnson Counter outputting a sample clock and a synchronized digital code at a multiple of the sample clock. The digital code drives a digital-to-analog converter to generate a frequency modulated control signal. The control signal is summed with the center frequency control from the digital locked loop digital filter to provide a frequency modulated center frequency control signal to the DLL oscillator.