| 摘要 |
An oscillating circuit having improved noise degeneration includes an oscillator and a noise degeneration circuit. The oscillator is adapted to provide a differential oscillating signal between first and second output terminals, and includes first and second transistors in communication with the first and second output terminals. The noise degeneration circuit includes cross-coupled capacitors and cross-coupled third and fourth transistors operated in a linear region. The noise degeneration circuit reduces the low frequency gm of the first and second transistors to lower the effect of flicker noise. At relatively high frequencies, the capacitors provide a virtual AC ground to the source terminals of the first and second transistors. The noise degeneration circuit receives a voltage signal from a biasing circuit adapted to track variations in electrical characteristics of the third and fourth transistors. |
