Power spectral densities of bit and word-interleaved line-coded channels for Gbit/s transmission

General formulas are presented for the power spectral densities (PSDs) of bit and word-interleaved line-coded digital signals, which are useful in the design of Gbit/s transmission systems. It is shown that word interleaving introduces very little spectral degradation for commonly used line codes, whereas the effects of bit-interleaving, though marked, are simply quantified. These predictions are confirmed by calculations of the PSDs using Monte Carlo simulations.