Fully integrated all-CMOS AM transmitter with automatic antenna tuning

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,
• wherein the phase-lock-loop further includes a phase detector and a loop filter, the loop filter being coupled between the phase detector and the oscillator, the phase detector and the loop filter being formed on the single monolithic chip;
• and
• a track and hold circuit coupled between the loop filter and the oscillator, the track and hold circuit being formed on the single monolithic chip, the track and hold circuit holding the phase-lock-loop state prior to disabling the oscillator in the event of a ‘space’ transmission.