Carrier modulation circuit

A carrier modulation circuit is used for modulating inputted sine wave signals by the aid of inputted digital modulating signals so as to obtain modulated output signals. The carrier modulation circuit comprises a modulating unit and a power amplifying unit. The modulating unit is a baypass circuit connected to an input position of the sine wave signals and consists of a trap filter circuit controlled by a first switch, the first switch is an electric control switch, and the digital modulation signals are control signals of the first switch. When the first switch is in a switch-on state, the trap filter circuit absorbs bypasses of the sine wave signals, when the first switch is in a switch-off state, the sine wave signals are transmitted to a post-stage circuit, and the control signals modulate the sine wave signals into modulating signals which carry effective information carried by the digital modulating signals during the processes of driving the first switch to be switched on and switched off. The power amplifying unit is used for amplifying the modulating signals. The carrier modulation circuit not only can meet the requirements of stability and reliability, but also can meet the requirements of lower cost and power consumption.