EMULATING NARROW BAND PHASE-LOCKED LOOP BEHAVIOR ON A WIDE BAND PHASE-LOCKED LOOP

摘要

A phase-locked loop circuit for providing a tightly controlled capture range for locking an output signal to a data signal, while also providing a wide frequency capture range for initially pulling the output signal within a wider, predetermined frequency range. The apparatus detects a frequency difference between at least one reference signal and an output signal, and generates a frequency error signal in response to the frequency difference. A phase difference is detected between a received input signal and the output signal, and a phase error signal is generated in response to the phase difference. The frequency error signal and the phase error signal are combined to control the frequency of the output signal by controlling a voltage-controlled oscillator.