Subband coding of cyclostationary signals with overdecimated filter banks

We consider optimal orthonormal filter banks for subband coding of wide sense cyclostationary signals, with N-periodic second order statistics. An L-channel over decimated uniform filter bank, with N-periodic analysis and synthesis filters, is used as the subband coder. An average variance condition is used to measure the output distortion. We show that for at least three potential bit allocation strategies, the optimum filter bank is a principal component filter bank. This is in the same vein as our earlier results on subband coding with maximally decimated filter banks.