Spread spectrum is
|“||[t]he technique whereby energy in a relatively narrow-band communication channel is spread over a much wider energy spectrum.||”|
|“||a modulation technique first developed to hide military communications amid natural noise and other signals. More recently, spread spectrum has been used to permit low-power signals to share spectrum with other services.||”|
|“||a technique in which a signal is spread over a much larger frequency range than the minimum required to deliver the message. It is often used by the military for antijam purposes. It is used by the commercial sector in CDMA mobile telephone systems and wireless LANs.||”|
As the name implies, the original modulating signal is spread over a wide range of frequencies (bandwidth) for transmission. Interference from conventional signals or other spread spectrum signals appear as noise to the system, and can be eliminated.
There are several types of spread spectrum systems, including: