FREQUENCY SYNTHESIS CIRCUIT FOR THE GENERATION OF AN ANALOGOUS SIGNAL WITH A DIGITALLY STEPWISE TUNABLE FREQUENCY

摘要

The frequency-synthesising circuit has a phase comparator (dp) in the form of a digital circuit whose inputs receive digital signals and whose output signal is digital. A reference signal (fr) lies at the clock input of the phase comparator and a digital accumulator (ac) whose output is connected to the first input of the phase comparator. A count value that determines the frequency of the signal (fs) is passed to the input of the accumulator. The vco (vo) outputs the signal (fs) and a data signal representing it for passing to the second input of the phase comparator.