Spectral analysis of maximum entropy multitrack modulation codes

In this correspondence the problem of calculating the power spectral density of a constrained maxentropic vector sequence {a⁽ⁿ⁾}, a⁽ⁿ⁾ = [a_i⁽ⁿ⁾]0<i<N - 1, is considered. The constraints of the constituent sequences {a_i⁽ⁿ⁾}are defined by the soflc systems S_i presented by the directed graphs G_i, 0 < i < N - 1, but the vector sequence itself is constrained additionally, and given by a function φ of constituent graphs (G = φ(G₀, ⋯, G_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.