| 摘要 |
PURPOSE:To make use of electric power of switching effectively and also to make it possible to realize operation with a single electric power source by incorporating a transistor switch circuit in the switching control circuit of a high-frequency change- over circuit. CONSTITUTION:In transmission, a positive bias is supplied to transmitting bias terminal VT and receiving bias terminal VR is held at zero voltage. Electric current from terminal VT flows through resistance R1, choke coil L1, diode D1, coil L2, transistor TR1 and light emission diode D2 in sequence. Further, diode D2 turns off since transistor TR2 turns off. In reception, terminal VT is held at zero voltage and terminal VR is applied with the positive bias. By way of TR2, coil L3, diode D2 and coil L2, bias current from terminal VR is accumulated in capacitor C4 and then supplied to reception part RX. |
