A design method for a periodically time-varying digital filter for spectrum scrambling
R. Ishii, Masahiro Kakishita · IEEE Transactions on Acoustics Speech and Signal Processing · 1990
A spectrum scrambling method is presented using the bifrequency map. It is proposed that a periodically time-varying digital filter can be designed using a bifrequency map and a conventional filter design method. A structure for a periodically time-varying digital filter which can be implemented easily on a digital signal processor is presented.>