| 摘要 |
PURPOSE:To secure the communication area by preventing production of an area to be in system-down automatically. CONSTITUTION:A detection circuit 1 detects whether or not other fundamental frequency signals are received at a required level or over and provides an output of H/L level signal respectively. An automatic switch 5 is closed/open depending on the H/L level signal respectively and gives the L/H level signal to a switch circuit 6, which is used to start/stop the oscillation by an oscillation element 2. The other fundamental frequency signals obtained through the automatic switch 5 and the fundamental frequency signal obtained by the oscillating element are alternately given to the circuit comprising a PLL synthesizer 3 and a voltage controlled oscillator 4 to oscillate a required frequency. |
