Transmission circuit and communication apparatus employing the same

• Main Authors: MORIMOTO SHIGERU, MATSUURA TORU
• Format: Patent
• Language: English
• Published: 01.09.2009
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION

A transmission circuit is provided which can output a stable transmission signal independently of the temperature characteristics of an amplitude modulating section. A signal generating section generates an amplitude signal and a phase signal. A regulator supplies a voltage which is controlled, depending on the amplitude signal, to the amplitude modulating section. An angle modulating section subjects the phase signal to angle modulation to output an angle-modulated signal. A temperature detecting section outputs temperature information of the amplitude modulating section. A gain control section controls a gain of a variable gain amplifier based on the temperature information of the amplitude modulating section. The variable gain amplifier amplifies the angle-modulated signal using the gain controlled by the gain control section. The amplitude modulating section subjects the angle-modulated signal to amplitude modulation using a voltage which is controlled, depending on the amplitude signal, to output an amplitude-modulated signal.