Patent ID: 7031675

Claim:
An FM transmitter, comprising: a phase lock loop including a charging pump, wherein said phase lock loop further includes a phase comparator, a loop filter, a voltage controlled oscillator, and a counter; an adder to add up a frequency shift to a signal of said phase lock loop, said frequency shift corresponding to a transmission signal; a controller to receive a signal regarding start and idle of said phase lock loop, and to output a control signal to control an output of said charging pump; and a buffer amplifier to input a signal from said phase loop look and to output a signal to an antenna, wherein said controller is coupled to further receive a start/idle signal of said buffer amplifier and to output a control signal to hold an output of said charging pump in a high resistance state, and wherein said phase lock loop is controlled so as to be held in closed loop control for a period from a start-up timing of said phase lock loop, and held in open loop control for other periods.