| 摘要 |
Home system for altitude and frequency customised one-way logical communications using cylindrical ultrasonic transducers composed of a piezoxide doublet of simple manufacture or of an electret and of an incremental oscillator. The invention relates to a home system for communications between sensors and alarm stations which can be taken through telephone transmitters. The transmitters and receivers, which can operate on a chosen frequency, are composed of a same transducer comprising an incremental oscillator associated with a cylinder vibrating at ultrasonic frequencies in a horizontal plane. This cylinder, based on a vertical axis 1, can be either a doublet 2 formed of a steel sleeve 3 adhesively bonded to a piezoxide cylinder 4 or an electret. The links, characterised with precision in altitude and frequency, are independent of the azimuth. The number, category, altitude and azimuth can readily be reviewed. <IMAGE>
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