Patent ID: 6289205
Filing Date: 2001-09-11
Classification: H03F,H03G

Abstract:
A transmitter for communication devices, which comprises:a high-frequency power amplifier for amplifying the high-frequency signal to be transmitted, which high-frequency power amplifier comprises a transistor with a collector-emitter voltage and an emitter current, and an output stage (4) for giving an amplified high-frequency signal, andmeasuring devices for measuring the power of the high-frequency signal comprising:high-frequency voltage measuring devices and current measuring devices for measuring the voltage and current of the high-frequency signal in said output stage, andhigh frequency power measuring devices for calculating the power of the high-frequency signal on the basis of the measured high-frequency voltage and high-frequency current, and whereinthe high-frequency voltage measuring devices comprise a first differential amplifier for forming a measurement signal proportional to the high-frequency collector-emitter voltage, a first rectifier for forming the absolute value of the measurement signal proportional to the collector-emitter voltage, and a first integrator for forming a measurement signal proportional to the mean value of the collector-emitter voltage of the transistor,the high-frequency current measuring devices comprise a second differential amplifier for forming a measurement signal proportional to the high-frequency emitter current, a second rectifier for forming the absolute value proportional to the emitter current and a second integrator for forming a measurement signal proportional to the mean value of the emitter current of the transistor, andthe measuring devices of the high-frequency power comprise a third integrator and a multiplier circuit for forming and inputting to said third integrator a measurement signal proportional to each instantaneous power by multiplying the high-frequency measurement signal proportional to the collector-emitter voltage by the high-frequency measurement signal proportional to the emitter current for forming a measurement signal proportional to the mean value of the power output of the third integrator.