发明名称 |
APPARAT FOR INBROTTSSEKRING, VID VILKEN ELEKTROMAGNETISK STRALNING OCH ULTRALJUDSTRALNING SAMTIDIGT UTSENDES |
摘要 |
Burglar alarm apparatus includes an ultrasonic transmitter and an electromagnetic radiation transmitter whose signals are Doppler frequency shifted by an object moving through the radiation fields, the signals being received by respective demodulating receivers which provide respective electrical signals corresponding to the Doppler frequency. Frequency conversion apparatus is connected to one of the receivers to convert the output frequency thereof by a predetermined ratio to normalize or equalize the frequencies and a signal comparison circuit is provided to produce a signal in response to a ratio of the Doppler shifted signals within a predetermined tolerance range. |
申请公布号 |
SE411000(B) |
申请公布日期 |
1979.11.19 |
申请号 |
SE19770003443 |
申请日期 |
1977.03.25 |
申请人 |
* SIEMENS AG |
发明人 |
W * HEYWANG;M * GUNTERSDORFER;P * KLEINSCHMIDT |
分类号 |
G08B13/00;G08B13/16;G08B13/24;(IPC1-7):08B13/00 |
主分类号 |
G08B13/00 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|