Devices for sending and receiving a modulated signal

摘要

The sender includes a first source of M-ary symbols and a second source of M'-ary symbols, with M'>M>1, for example M=2, M'=8. The frames delivered by one of the sources are interleaved into successive blocks each including symbols obtained from at least two frames. Each block gives rise to a burst of modulated signal produced either by a first modulator of M-ary symbols or by a second modulator of M'-ary symbols. In response to a change of the active source, certain M-ary symbols originating from the first source are converted into M'-ary symbols to produce at least one block of M'-ary symbols submitted to the second modulator and including both symbols from at least one frame delivered by the second source and symbols obtained by conversion of M-ary symbols from at least one frame delivered by the first source.