High agility frequency synthesizer phase-locked loop

摘要

A highly agile low phase noise frequency synthesizer is provided for rapid generation of frequency specific signals. The frequency synthesizer is capable of rapidly generating signals at different output frequencies while maintaining low cross-coupling. Two or more signal generators utilize a reference frequency to generate two or more signals. These signals are limit processed to reduce cross-coupling prior to being presented to a switch. Responsive to a control signal, the switch outputs one of the signals to a frequency modification device, such as a frequency divider or multiplier. Responsive to a control signal, the frequency modification device scales the frequency of the switch output to convert the frequency of the switch output signal to a desired output frequency. By maintaining sufficient frequency separation between the switch input signals cross-coupling and phase noise is minimized and implementation on an integrated circuit may be achieved.

主权项

1. A method for rapidly generating a signal at an output frequency for use in a communication device comprising:
providing a reference signal at a reference frequency to a first signal synthesizer configured to generate a first signal at a first frequency; generating the first signal with the first signal synthesizer; providing the reference signal at the reference frequency to a second signal synthesizer configured to generate a second signal at a second frequency; generating the second signal with the second signal synthesizer; providing the first signal and the second signal to a switch; responsive to a control signal, selectively outputting either the first signal or the second signal from the switch as part of a switching operation; responsive to switching operation, applying a first frequency modification to the first signal or a second frequency modification to the second signal to thereby generate a frequency specific signal at an output frequency; and outputting the frequency specific signal without the frequency specific signal passing through any switches after the frequency modification, such that the switching operation is the only switching operation when producing the frequency specific signal.