Aopen aoi-812 사용자 설명서

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13.  What is Spread Spectrum 
Spread Spectrum technology is a wideband radio frequency technique developed by the military 
for use in reliable, secure, mission-critical communication systems. It is designed to trade off 
bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is 
consumed than in the case of narrowband transmission, but the trade off produces a signal that 
is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of 
the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a 
spread –spectrum signal looks like background noise. There are two main alternatives, Direct 
Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).