Pseudonoise test signals and the fast Fourier transform

Recent published work has indicated a growing interest in the combined use of periodic pseudonoise (p.n.) test signals and the fast Fourier transform (f.f.t.). However, it has been noted by Barker and Davy that the period of pseudonoise sequences are such that it is not possible to use the most efficient form of the f.f.t. This letter points out ways round the problem by drawing attention to a previously published result in this area. In addition, a little known algorithm that directly exploits the f.f.t. to generate pseudonoise is given.