Patent ID: 6498538
Filing Date: 2002-12-24
Classification: H03L,Y10S

Abstract:
A system for providing a low noise signal having a selected frequency with a wide frequency tuning range, the system comprising:a phase locked loop system that receives an input signal and provides first and second, substantially inverted output signals, with a selected frequency tuning range between a selected frequency minimum f(min) and a selected frequency maximum f(max); a bandpass filter system that receives the phase locked loop system first and second output signals, that has a first state in which the received first and second output signals are processed without substantial differential attenuation at any frequency, that has a second state in which the received first and second output signals are substantially attenuated except in a selected frequency range, that provides a first output signal that is substantially the same as the signal received by the phase locked loop system, and that provides a second output signal that has low noise and has at least one selected frequency component within the selected frequency range; and an activation circuit that switches the bandpass filter system between the first state and the second state.