| 摘要 |
PURPOSE: To control a transmission output without the need for adjustment of output power and temperature compensation or the like. CONSTITUTION: A modulation signal from an orthogonal modulator 2 is fed to a mixer 4 and a 2nd local oscillation signal from a 2nd local oscillator 6 is fed through a variable gain amplifier 5. A transmission signal from the mixer 4 is fed to a power amplifier 8 through a step attenuator (ATT) 7 and fed to an antenna 11 through a directional coupler 9 and an isolator 10. The signal extracted from the directional coupler 9 is fed to a comparator 13 via a detector 12. Furthermore, a reference voltage is fed to the comparator 13 from a reference voltage setting section 14 and an output of the comparator 13 is fed to a control section of a variable gain amplifier 5 and the gain is controlled so that a Dc voltage from the detector 12 and a reference voltage from the reference voltage setting section 14 are equal to each other. Moreover, the attenuation of the step attenuator 7 is set by an attenuation setting section 15 according to a transmission output control signal from a base station. |
