| 摘要 |
PURPOSE:To remove a noise component, and also to obtain a carrier wave extracting circuit of high response speed in a state that a band of a BPF is kept wide. CONSTITUTION:This carrier wave extracting circuit is constituted by adding an AFC circuit by frequency conversion, to a BPF circuit, and a phase modulator is inserted on the service line of a local oscillation signal of a frequency convertng circuit of the output side, and the modulation is executed so that an output of this modulator has the same noise spectrum as an output of the BPF, by which these noise components are mutually negated by said frequency converter. In this way, a noise component of an output is attenuated enough even if the band of the BPF is wide, and above all, as for a burstlike input carrier wave, its response speed is high, and also the noise component is attenuated enough. |
