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  2. Radar signal characteristics - Wikipedia

    en.wikipedia.org/wiki/Radar_signal_characteristics

    The pulse width ( ) (or pulse duration) of the transmitted signal is the time, typically in microseconds, each pulse lasts. If the pulse is not a perfect square wave, the time is typically measured between the 50% power levels of the rising and falling edges of the pulse. The pulse width must be long enough to ensure that the radar emits ...

  3. Security alarm - Wikipedia

    en.wikipedia.org/wiki/Security_alarm

    A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.

  4. Radio-frequency identification - Wikipedia

    en.wikipedia.org/wiki/Radio-frequency_identification

    Radio-frequency identification. Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder called a tag, a radio receiver, and a transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader ...

  5. Perimeter surveillance radar - Wikipedia

    en.wikipedia.org/wiki/Perimeter_Surveillance_Radar

    Resolution: a radar that operates at higher frequencies and with narrower beams will determine target positions most accurately. Low false alarm rates: a radar that puts out false targets is at best an irritant and tactically can confuse the security team. A good PSR should have a designed false alarm rate of two or less false alarms per day.

  6. Distress signal - Wikipedia

    en.wikipedia.org/wiki/Distress_signal

    A distress signal, also known as a distress call, is an internationally recognized means for obtaining help. Distress signals are communicated by transmitting radio signals, displaying a visually observable item or illumination, or making a sound audible from a distance. A distress signal indicates that a person or group of people, watercraft ...

  7. Automatic identification system - Wikipedia

    en.wikipedia.org/wiki/Automatic_identification...

    A graphical display of AIS data on board a ship. The automatic identification system (AIS) is an automatic tracking system that uses transceivers on ships and is used by vessel traffic services (VTS). When satellites are used to receive AIS signatures, the term Satellite-AIS (S-AIS) is used. AIS information supplements marine radar, which ...