Patent ID: 6038428
Filing Date: 2000-03-14
Classification: H03G

Abstract:
A power control circuit for use in a transmitter having an antenna wherein a signal transmission power level is controlled by a power level control sginal, said power control circuit comprising:a modulator for modulating an input signal to be transmitted by a first local oscillating signal;a mixer for mixing said modulated input signal with a power adjusted second local oscillating signal;a variable gain control amplifier for adjusting a power of a second local oscillating signal fed thereto in response to a control signal and producing said power adjusted second local oscillator signal fed to said mixer;an attenuator for attenuating a signal output from said mixer, wherein attenuation of said signal output from said mixer is controlled according to said power level control signal;a power amplifier for amplifying a signal output from said attenuator and for radiating an amplified output signal via said antenna;a power level detector for detecting a transmission power level of said amplified signal from said power amplifier; anda comparator for comparing the transmission power level output from said power level detector with a reference signal corresponding to a setting of the transmission output power for producing said control signal for adjusting a gain of said variable gain controlled amplifier in response to the comparison.