Easier multiplexing of variuous sources of information: voice, data, video.
Can accommodate digital error-control codes
Enables encryption of the transferred signals
More secure link
Digital Modulation The modulating signal is respresented as a time-sequence of symbols or pulses. Each symbol has m finite states: That means each symbol carries n bits of information where n = log 2 m bits/symbol. ... 0 1 2 3 T One symbol (has m states – voltage levels ) ( represents n = log 2 m bits of information ) Modulator
Factors that Influence Choice of Digital Modulation Techniques
A desired modulation scheme
Provides low bit-error rates at low SNRs
Performs well in multipath and fading conditions
Occupies minimum RF channel bandwidth
Is easy and cost-effective to implement
Depending on the demands of a particular system or application, tradeoffs are made when selecting a digital modulation scheme.