Patent ID: 6687488
Filing Date: 2004-02-03
Classification: H04B

Abstract:
A transmitter comprising:an oscillator forming part of a phase-lock loop (PLL), the oscillator in combination with the phase-lock loop generating a transmit frequency of the transmitter in response to a frequency reference, the oscillator including a resonant network; a modulator, a portion of said oscillator and said modulator being formed on a single monolithic chip, wherein part of the resonant network is formed on the monolithic chip, the resonant network of the oscillator being completed by an antenna formed external to the single monolithic chip, a resonance frequency of said resonant network being automatically tuned by the phase-lock loop to the transmit frequency, and wherein the oscillator includes a differential structure of varactor diodes for tuning a resonance point of the antenna to the frequency of the oscillator; and a varactor charge pump formed on the single monolithic chip to provide a bias charge for varactor diodes in the differential structure of varactor diodes.