Spectral analysis of maximum entropy multitrack modulation codes

The problem of calculating the power spectral density of a constrained maxentropic vector sequence {a/sup n/}, a/sup n/=[a/sub i//sup n/]/sub 0/spl les/i/spl les/N-1/, is considered. The constraints of the constituent sequences {a/sub i//sup n/} are defined by the sofic systems S/sub i/ presented by the directed graphs G/sub i/, 0/spl les/i/spl les/N-1, but the vector sequence itself is constrained additionally, and given by a function /spl phi/ of constituent graphs (G=/spl phi/(G/sub 0/, /spl middot//spl middot//spl middot/, G/sub N-1/)). This class of vector constraints is met in parallel multitrack recording. The general case of a simultaneous recording on N tracks is considered, assuming that the common vector constraint is track-invariant.