Active cancellation is a theoretical military jamming system that involves the sampling of an incoming radar signal, analyzing it, then returning this signal slightly out of phase, thus "canceling" it out. While there are no official systems using this in service, it is rumored to be in use on United States Air Force stealth aircraft like the B-2, F-117, F-22A, and possibly the F-35. It is also speculated that the Thales SPECTRA aircraft protection suite also uses this system. This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll. ... Look up Phase in Wiktionary, the free dictionary Phase may refer to: Phase (matter), a physically distinctive form of a substance, such as the solid, liquid, and gaseous states of ordinary matter Phase (waves), the time position (or angle in the complex plane) within a cycle of a periodic waveform... The United States Air Force (USAF) is the aerial warfare branch of the United States armed forces and one of the seven uniformed services. ... This article or section is in need of attention from an expert on the subject. ... The Northrop Grumman B-2 Spirit is a multi-role stealth bomber able to drop conventional and nuclear weapons. ... The United States Air Forces F-117A Nighthawk is the worlds first operational aircraft designed to exploit low-observable stealth technology. ... F-22 Raptors over California The F-22 Raptor is a highly maneuverable stealthy fighter aircraft built by Lockheed Martin Aeronautics and Boeing Integrated Defense Systems. ... The F-35 Joint Strike Fighter The F-35 Joint Strike Fighter (JSF) is a fighter plane currently in early development by Lockheed Martin (with partners Northrop Grumman and BAE SYSTEMS.) The primary customers are the United States armed forces and the United Kingdom (RN and RAF), but the Netherlands... The Thales SPECTRA (Système de Protection et dÉvitement des Conduites de Tir du Rafale, Self-Protection Equipment Countering Threats to Rafale Aircraft) is an integrated defensive aids suite developed by Thales Group for the Dassault Rafale series of fighter aircraft. ...

See also

• Active noise control