| abstract |
The high frequency oscillator comprises a reference oscillator, a phase-locked loop circuit with a phase frequency detector, a charge pump, a ring oscillator and a divider, the reference oscillator being coupled to the phase frequency detector for frequency control. The ring oscillator is a symmetrical delay cell oscillator containing two amplifiers with a dual output stage for providing I/Q output signal generation. The reference oscillator works in the range of 1.25-1.5 GHz and is a Colpitts type digital controlled frequency synthesizer with an external tank circuit for providing a low phase noise, and the dividing factor of the divider is four for providing a tuned output range of 5 to 6 GHz. The phase-locked loop circuit is integrated together with the reference oscillator into an integrated circuit, using advantageously a BICMOS Silicon/Germanium process, which is well suited for RF applications. |