| 摘要 |
<p>PROBLEM TO BE SOLVED: To automatically detect the presence/absence of a fault using an inexpensive means. SOLUTION: When a speaker 12 and a microphone 13 are arranged adjacently, while a fault such as disconnection is not taking place in a broadcasting system, howling occurs in a loop consisting of a voice signal line, to which a selector switch 11 is connected and, e.g. an amplifier 5n belongs, and a fault detection device 10. The howling that takes place is made to grow on the loop, a level detector 17 detects the level of the howling that has grown, and a displaying part 18 displays the level. In case a fault exists, a level displayed by the part 18 becomes almost zero level because howling does not take place, and according to this, the existence of the fault can be detected. Excessive noise sound can be prevented from being generated, because a compressor 16 prevents the howling from growing too large. A switch that turns off at a time when a level of the detector 17 reaches a prescribed value may be used, instead of the compressor 16.</p> |
