| 摘要 |
PURPOSE:To enable the transmission of a charging signal through a transport circuit, by converting an out-of-band AC signal into an inside-band AC signal and then carrying out the relaying between control stations in order to transmit the out-of-band AC signal through a transport circuit. CONSTITUTION:The block diagram shows an example of the transmission of a single direction. The signals given from an exchange EXa of a control station MSa are branched by a 3-turn transformer Ha, and only the audio signal is separated by an LPFa. These signals are applied to a mixing amplifier MAa. While an AC signal fa is extracted by a BPFa to drive a relay A. Then an inside-band AC signal fb of 3,400Hz, etc. for example is transmitted from a signal generator SGa and via a contact (a) and applied to the amplifier MAa. As a result, the signal fa is converted into a signal fb and then transmitted to a transport circuit Lc to be transmitted smoothly. |
