Continuous phase modulation: Difference between revisions

Revision as of 02:24, 3 June 2017

Revision as of 00:00, 12 June 2020

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== Phase memory ==

Each symbol is modulated by gradually changing the phase of the carrier from the starting value to the final value, over the symbol duration. The modulation and [[demodulation]] of CPM is complicated by the fact that the initial phase of each symbol is determined by the cumulative total phase of all previous transmitted symbols, which is known as the ''phase memory''.

Therefore, the optimal receiver cannot make decisions on any isolated symbol without taking the entire sequence of transmitted symbols into account. This requires a [[Maximummaximum Likelihoodlikelihood|maximum-likelihood]] Sequencesequence Estimatorestimator (MLSE), which is efficiently implemented using the [[Viterbi algorithm]].

== Phase trajectory ==