| 摘要 |
PURPOSE:To reproduce correctly the reference level of a DC signal at the reception side by providing a synthesizing circuit synthesizing a DC signal to be sent and a pulse signal and outputting a signal representing the reference value in the peak value of a pulse signal component in the synthesizing signal. CONSTITUTION:When the output pulse voltage signal Vc of a pulse oscillation circuit is at a positive level, a transistor (TR) 14 is turned off. A current equal to an input signal Ii as an envelope output signal flowing to a TR 12 flows to a TR 13 which becomes an output current. That is, the relation of Ii=Io exists where Io is the output current of the synthesizing circuit. When the signal Vc is negative, the TR 14 is turned on, since the current flowing to the TR 12 flows through TRs 14, 15, the TR 13 is turned off. Thus, the output current Io is 0. The output current Io being at 0 level when the signal Vc is at a negative level is obtained. That is, a pulse shaped signal component representing the zero level of the reference level is included in the synthesizing signal Io. |
