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Radar Gun
EditA radar speed gun (also radar gun and speed gun) is a device used to measure the speed of moving objects. It is used in law-enforcement to measure the speed of moving vehicles and is often used in professional spectator sport, for things such as the measurement of bowling speeds in cricket, speed of pitched baseballs, athletes and tennis serves. A radar speed gun is a Doppler radar unit that may be hand-held, vehicle-mounted or static. It measures the speed of the objects at which it is pointed by detecting a change in frequency of the returned radar signal caused by the Doppler effect, whereby the frequency of the returned signal is increased in proportion to the object's speed of approach if the object is approaching, and lowered if the object is receding. Such devices are frequently used for speed limit enforcement, although more modern LIDAR speed gun instruments, which use pulsed laser light instead of radar, began to replace radar guns during the first decade of the twenty-first century, because of limitations associated with small radar systems.
References
- Kennedy, Pagan (30 August 2013). "Innovation: Who Made That Traffic Radar?". The New York Times. https://www.nytimes.com/2013/09/01/magazine/who-made-that-traffic-radar.html. Retrieved 1 September 2013.
- "Speeders in Connecticut to Face Real Radar Test". The New York Times. 6 February 1949. https://www.nytimes.com/1949/02/06/archives/speeders-in-connecticut-to-face-real-radar-test.html. Retrieved 1 September 2013.
- "Radar Works on Speeders; Year's Test on Long Island Shows System is Costly". The New York Times. 8 February 1949. https://www.nytimes.com/1949/02/09/archives/radar-works-on-speeders-years-test-made-on-long-island-shows-system.html. Retrieved 1 September 2013.
- "Mobil Scanners and Radar Detection Law in the US". Todd L. Sherman. 2011. http://www.afn.org/~afn09444/scanlaws/. Retrieved September 11, 2011.
- "Radar detectors FAQ". Whistler Group. http://www.whistlergroup.com/faq-detectors-answers.asp#19. Retrieved 2010-09-17.
- "California Motor Vehicle Code". State of California. 2011. http://www.dmv.ca.gov/pubs/vctop/d17/vc40802.htm. Retrieved February 15, 2011.
