By assuming engineering approximation and using theorem[1] for orthogonal expansion of D（Fn⊕CLm）

which is the D-transform of Fn⊕CLm

general expressions of normalized autocorrelation function and normalized power spectral density function of Fn⊕CLm have been derived

where Fn⊕CLm is the digital modulation of the combined code by a square wave with a frequency M times that of the clock frequency. Engineering design examples have also been given.