| 摘要 |
<p>PURPOSE:To perform signal transmission regardless of whether a transmission- side and a reception-side equipment are connected to power lines or not, by providing an electric path having an inserted control element which turns on only when a power voltage has a prescribed polarity between the power lines, and supplying the element with a signal which has long time width enough to have transition from one power voltage polarity to the other. CONSTITUTION:A signal (B) led out of the secondary winding of a transformer 5 through a polarity detecting circuit 6 is supplied to a serial signal geneating circuit 7 and then when the voltage waveform A of one power line is plus, a binary signal (C) is sent out for a long period enough to have plus-to-minus polarity transition. This signal (C) is polarity-inverted by an inverter 10 and then converted into a light signal by the light emitting diode of a photocoupler 11. This light signal is converted into a signal with a waveform (G) by a light emitting diode 12. At a reception side, the signal with the waveform (G) is converted into a light output through a light emitting diode 12 and the signal is supplied to a controller which is not shown in the figure. Thus, signal transmission is carried out regardless whether a transmission-side and a reception-side equipment are connected to the power lines or not.</p> |
