SPREAD SPECTRUM MODULATION TECHNIQUES -spread spectrum - those modulation methods that are producing a signal whose spectrum is more wider than of the data signal, the occupied frequency band being independent by the signal of data band. -The signals with spread spectrum of direct sequence type BPSK (BPSK-DS-SS) -The signals with spread spectrum of direct sequence type QPSK – DS–SS - Frequency hopping spread spectrum signals (FH-SS)