| 摘要 |
<p>The alarm system uses a radar hyperfrequency Doppler effect detector using the S-band. The detector (2) is connected to a microprocessor (3). The detector has around it several ranges of operation defining a series of zones in which a person (4) may be detected. When the detector determines that there is a person in the farthest zone (a) at 30m, this information is transmitted to the microprocessor (3) which reduces the range of sensitivity of the detector to zone (b) at 18m. If nothing is detected at this range the sensitivity is returned to the larger zone. However, if a person is detected in the smaller zone a pre-alarm signal is issued and the range of sensitivity is reduced still further to 12 and then to 6 metres. If no signal is detected within these ranges the range is extended again but, if a person is detected the full alarm is initiated.</p> |
