Chapter 2 Direct-Sequence Systems

Abstract

A spread-spectrum signal is one with an extra modulation that expands the signal bandwidth greatly beyond what is required by the underlying coded-data modulation. Spread-spectrum communication systems are useful for suppressing interference, making secure communications difficult to detect and process, accommodating fading and multipath channels, and providing a multiple-access capability. Spread-spectrum signals cause relatively minor interference to other systems operating in the same spectral band. The most practical and dominant spread-spectrum systems are direct-sequence and frequency-hopping systems.