| 摘要 |
A sound level alarm device sequentially listens to the sound level of an enclosure or area for a first predetermined interval of time, and thereafter does not listen to the sound level of the area for another predetermined interval of time. The circuit sounds an alarm upon detection of a sound level of a predetermined magnitude measured during the first time interval. The circuitry is designed for omitting quick, sharp noises such as a cough, hand clap, book dropping, or the like. The apparatus is advantageously used in class rooms, laboratories, libraries, and play rooms as a teaching aid wherein people with loud noisy habits are electronically assisted in overcoming these undesirable aspects of their life style.
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