Wide band, low noise, fine step tuning, phase locked loop frequency

Abstract

A wide bandwidth, low noise, fine frequency step phase locked loop frequency synthesizer (10) and processing method. The synthesizer (10) includes a first divider (16) for dividing a first signal provided by a reference frequency source (12). A first phase locked loop (20) is provided for receiving a divided first signal from the first divider (16) and providing an intermediate frequency signal in response thereto. The first phase locked loop (20) includes a first phase detector (22) for comparing the phase of the first signal to the phase of a first feedback signal and providing a first phase difference signal in response thereto. The first phase locked loop (20) includes a first voltage controlled oscillator (30) for providing the intermediate signal in response to the first phase difference signal. The first phase locked loop (20) includes a first mixer (32) for mixing the intermediate signal with a second signal at a second frequency F2 and providing the first feedback signal in response thereto. A second divider (38) is included in the first phase locked loop (20) for dividing the first feedback signal prior to its application to the first phase detector (22). A third divider (39) is provided for shifting the frequency of the intermediate frequency signal, and a second phase locked loop (40) is coupled to the third divider for processing the frequency shifted intermediate frequency signal and providing an output frequency signal from the synthesizer. The second phase locked loop (40) includes a second phase detector (42) for comparing the phase of the shifted intermediate signal to the phase of a second feedback signal and providing a second phase difference signal in response thereto. A second voltage controlled oscillator (50) is included for providing the output frequency signal from the synthesizer (10).