Carrier wave modulating method and circuit

The invention discloses a carrier wave modulating method and a circuit. The method comprises the following steps of: firstly, performing modulation process, namely, connecting a bypass circuit formed by a trap filter circuit which is controlled by a first switch at the input position of a sine wave signal, wherein the first switch is an electric control switch; a digital modulating signal is a control signal of the first switch; when the first switch is in closed state, the trap filter circuit absorbs a sine wave signal bypass; and modulating the sine wave signal as a modulating signal which bears the effective information carried by the digital modulating signal when the control signal drives the first switch to open or close; secondly, performing power amplification process, namely, performing amplification process for the modulating signal through a power amplifying circuit; and finally, performing output filter process, namely, connecting the signal of which the power is performed power amplification to a filter circuit so as to filter out a noise wave. The carrier wave modulating method and circuit not only meets the requirements of stability and reliability, but also meets the requirements of low cost and small power consumption.