Revision as of 02:53, 15 October 2007 edit Dawnseeker2000 (talk \| contribs) Autopatrolled, Extended confirmed users, File movers, New page reviewers, Pending changes reviewers, Rollbackers 535,883 edits m wikify carrier ← Previous edit		Revision as of 03:35, 15 October 2007 edit undo Dawnseeker2000 (talk \| contribs) Autopatrolled, Extended confirmed users, File movers, New page reviewers, Pending changes reviewers, Rollbackers 535,883 edits m wikify phase shift Next edit →
Line 4: '''Continuous phase modulation''' ('''CPM''') is a method for [[frequency modulation\|modulation]] of data commonly used in [[wireless modem]]s. In contrast to other coherent digital [[phase modulation]] techniques where the [[carrier wave\|carrier]] phase abruptly resets to zero at the start of every symbol (e.g. M-[[phase-shift keying\|PSK]]), with CPM the carrier phase is modulated in a continuous manner. For instance, with [[QPSK]] the carrier instantaneously jumps from a sine to a cosine (i.e. a 90 degree [[phase shift]]) whenever one of the two message bits of the current symbol differs from the two message bits of the previous symbol. This discontinuity requires a relatively large percentage of the power to occur outside of the intended band (e.g., high fractional out-of-band power), leading to poor [[spectral efficiency]].

Continuous phase modulation: Difference between revisions