A METHOD OF AND AN APPARATUS FOR EFFECTING A SMOOTH TRANSITION BETWEEN ADJACENT SYMBOL BURSTS TRANSMITTED IN DIFFERENT MODULATION FORMATS

摘要

A smooth transition is effected between adjacent digital information bursts transmitted in different modulation formats by selecting a first sequence for a first digital symbol burst to be transmitted, which first sequence comprises a set of end symbols with a first particular symbol pattern. A second sequence for a second digital symbol burst is also selected for transmission after the first digital symbol burst, which second sequence comprises a set of start symbols with a second particular symbol pattern. The first digital symbol burst is modulated in a first modulation format and the second digital symbol burst is modulated in a second modulation format different than the first modulation format. Thereafter, the modulated first and second digital symbol bursts are transmitted. The transmission of the second digital symbol burst starts upon completion of the transmission of the first digital information symbol at an instant so selected that transmission of the end set of bits of the first code sequence is synchronized in time with the start set of bits of the second code sequence.