| 摘要 |
PURPOSE:To prevent mis-reception of a receiver side by providing an output transformer using a pulse coded control signal to modulate a carrier wave and superimposing the modulated output on a power line, and a gate short-circuiting the primary winding of the output transformer in synchronizing with the control signal to suppress the distortion of a modulation signal superimposed on the power line. CONSTITUTION:A microprocessor 9 outputs a pulse coded control signal as shown in Fig. (a) based on an operation signal inputted frm a terminal I. A modulation section 10 modulates a carrier wave by using a control signal fed from the microprocessor 9 and outputs the modulation output shown in Fig. (b) to the primary side of the output transformer 11. The gate 12 short-circuits between terminals S1 and S2 at an L level voltage of the control signal and opens the S1, S2 by using the H level voltage. Through the constitution above, the primary side of the output transformer 11 is short-circuited based on the L level voltage of the control signal from the microprocessor 9. Thus, the primary side inductive load component being a cause to distortion is decreased to prethe effect on the secondary side and a modulation waveform shown in Fig. (d) is superimposed on an indoor power line. |
