Quadratic Multiplexing--A New Method for Secure Communication.

摘要

A secure digital multiplexing technique is presented which uses a pseudo-random process with a fundamental cycle length N. The method can handle D < N signal sequences of length M < N. The SNR's of the de-multiplexed signals is N/4DM for large N, even if the additive noise power is large. The de-multiplexer must compute the discrete Fourier transform of the pseudo-random sequence that is used to encode the signals. Information is carried in the phase differences between the frequency components of the multiplexed signal. De-multiplexing requires at least DMNlog2N arithmetic calculations. (Author)