Computer aids for code spectra calculations

A suite of computer programs has been developed to calculate the power spectral density of a wide range of transmission codes. Suitable user interfaces are provided for the automatic construction of the state diagram, the encode function and the codework matrices. The output includes the attractive analytical formula in closed-cosine form, the autocorrelation function and plots, in colour, for Dirac delta and raised-cosine pulses. The paper presents results on the analysis of zero-mean-disparity block codes, general binary/tertiary codes with multiaphabets and an adaptive code based on the Howells-Woodman Miller codes.