Patent ID: 7209717
Filing Date: 2007-04-24
Classification: H03F,H03G,H04L

Abstract:
1. An apparatus for a radio telecommunication system comprising: a modulation circuit for performing phase modulation and amplitude modulation; a phase detection circuit for detecting a phase component of a signal modulated by said modulation circuit; an amplitude detection circuit for detecting an amplitude component of the signal modulated by said modulation circuit; a power amplifier circuit for amplifying power of a transmission signal and outputting the amplified transmission signal; a feedback path for feeding a signal corresponding to an output level of said power amplifier circuit back to said amplitude detection circuit; a variable gain amplifier circuit provided on a forward path between said amplitude detection circuit and said power amplifier circuit for generating a control voltage for amplitude control of said power amplifier circuit; a loop filter for setting a frequency bandwidth of an amplitude control loop, said amplitude control loop including said feedback path and said forward path; precharge means for rapidly raising an output power of said power amplifier circuit from a low power level to a power threshold for building up output power of said power amplifier circuit; and level detecting means for detecting the level of a signal fed back through said feedback path, wherein said precharge means includes a current source and switch means connected in series with said current source, said switch means being configured to be turned on when building up the output power of said power amplifier circuit, and turned off based on the level detected by said level detecting means.