Patent ID: 7092682

Claim:
An electronic circuit for amplitude-modulating digital data transmitted via an antenna including a resonance circuit, said electronic circuit comprising: a modulation circuit, having a first transistor, for amplitude-modulating a carrier wave applied to the base of said first transistor into an amplitude-modulated wave in accordance with a signal wave applied to the emitter of said first transistor and for supplying said amplitude-modulated wave to said antenna via the collector of said first transistor; and a signal-wave generation circuit for inputting a first pulse signal in a rectangular waveform corresponding to said digital data, for generating said signal wave in such a manner as to correspond to a second pulse signal whose waveform is shaped so that the level at each rise time of each pulse of said first input pulse signal becomes higher than the high level in a steady state of said first signal and the level at each fall time of each pulse of said first input pulse signal becomes lower than the low level in the steady state of said first signal, and for applying said generated signal wave to the emitter of said first transistor.