Comment on ´Merit factor of Chu and Frank sequences´ (and reply)

For the original article see ibid., vol.26, no.25, p.2068-70 (1990). In the paper by Antweiler and Bomer, the merit factor of optimally decimated and cyclic time shifted Chu and Frank sequences was determined by a computer search. It was found that the merit factor and peak-to-side-peak ratios of the Frank sequences are better than those for Chu sequences. The commenter wishes to point out some facts that can significantly reduce the computer search time for the Chu and Frank sequences having the best merit factors and the best peak-to-side-peak ratios. Also, he shows by an example that some of the recently proposed generalised Frank sequences can have much better merit factor than the Frank sequences of the same length. In reply the original authors agree that the commenter has sketched some new invariance operations which depend heavily on the construction method for the sequences in question. However, these invariance operations can readily be deduced from the ones given in the authors´ paper and this is demonstrated by an example.