| 摘要 |
PURPOSE:To prevent the spread of a spectrum by providing a gate circuit decoding a base band pulse signal and a low pass filter so as to easily realize the multi-level modulation of the amplitude and phase. CONSTITUTION:The titled circuit is provided with a ring modulation circuit 41 modulating a carrier signal based on two kinds of base band pulse signals S1, S2, a gate circuit 42 applying multi-level modulation to the phase and amplitude of a carrier signal in response to the combination of the base band pulse signals S1, S2 and a low pass filter 43 provided between the ring modulation circuit 41 and the gate circuit 42. Thus, the multi-level modulation of the phase and amplitude including the on/off control of the carrier signal is realized with a simple constitution and the spread of spectrum of the carrier signal after modulation is prevented.
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