Transcrypt International, Inc.

Douglas A Heerman

An apparatus and method for creating voice privacy by performing frequency spectrum inversion in electronic voice transmission systems includes the steps of digitizing an analog signal and inverting the frequency spectrum of the digitized audio signal. From the inverted spectrum, a complex signal is created from which the real component is extracted to produce a real signal suitable for transmitting. The digital signal processing is performed entirely with software. The scrambling and descrambling processes are nearly identical, therefore, the same hardware and software may be used to scramble and descramble the signal. The apparatus may uses a 'rolling code' to increase the effectiveness of the scrambling.

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Raymond, NE, United States of America

Douglas A Heerman