Comparison of Biorthogonal and Bisimplex Codes

A comparison is made between simplex and orthogonal codes which have been modified by adding their individual complements. The bisimplex code thus formed has reduced efficiency so that the power used must be increased to obtain the same error rate as with the same size of biorthogonal code. It is found that the power advantage of the biorthogonal code is significant only when the code words are shorter than six or seven bits.