The power spectral density of the HDB2 and the HDB3 coded signals

Explicit mathematical relations for the power density spectra of HDB2 and HDB3-encoded signals were derived. The derivation started from the coding laws in the case of arbitrary and rectangular pulse shapes. The coding law was regarded as a block code including blocks of different lengths, the code table containing four alphabets. The similarity of the coding laws of HDB2 and HDB3-codes is reflected in the derivation of the spectral properties. The results are graphically represented. The representation is detailed enough to be also applicable to other zero-sequence substitution codes like CHBn.