Fast-settling multiple-loop adaptive frequency locking scheme for energy-efficient resonant FSK transmitter

An architecture for an energy-efficient frequency shift keying transmitter is presented, comprising a resonant tank oscillator with a loop antenna radiating inductor, a digitally controlled capacitor array, and interleaved frequency locked loops (FLLs). The interleaved FLLs allow frequency adaptation concurrent with data transmission, and retain frequency settings between bursts of data transmission, eliminating the need for dedicated frequency adaptation intervals prior to sending data.