Bandlimited covert data communications using zinc waveforms

A covert data communications signal is generated with zinc waveforms, which are formed from a complete set of mutually orthogonal zinc basis functions. It is shown that the data signal is covert since it is noise-like in the time-domain with a white and strictly bandlimited spectrum. The zinc data waveform is a baseband signal that can be compactly represented in a two-dimensional signal space, as a baseband Phase Shift Keyed (PSK) signal. Two demodulation techniques are developed and symbol error rate performance presented. Zinc waveforms are also employed as a spreading signal in a Direct Sequence Spread Spectrum (DSSS) communication system. The zinc DSSS signal is seen to be more covert than a standard binary Pseudo-Noise (PN) DSSS signal. Bit error rate performance is obtained for zinc DSSS systems, and compared to PN DSSS systems. The zinc communication systems outperform the more conventional communication systems and afford significant covert signal transmission.