| 摘要 |
<p>PURPOSE:To facilitate the identification of a confirmation signal, by making the frequency of the confirmation signal variable while a noise checking mechanism is provided to exclude the noise frequency band. CONSTITUTION:Probes at a transmitting section 10 and a receiving sectin 20 are connected to connection points A and B of a core wire 1 to be checked in a cable and the center frequency of a band filter 22 is set. At this point, when a noise or the like exists near the center frequency in the core connected, it passes through the filter 22 to be inputted into level decision circuits 23 and 24. When at least the circuit 24 with the lower set level is in a trigger, the center frequency of the filter 22 is reset through a register 28 by a command from a command circuit 27. In this manner, when the center frequency of the filter 22 is determined, it is commanded to a register 14 on the transmitting section 10 side connected through an air-core line 1' to set the devision ratio of a frequency dividing circuit 12. Thus, the frequency of the confirmation signal shall be the decision frequency. Then, the confirmation signal is transmitted to check the condition of the core wire 1.</p> |
