Privacy communication system employing time/frequency transformation
First Claim
Patent Images
1. A privacy communication system comprisingA. means for splitting a voice signal into a selected number of frequency bands;
- B. means for generating a pseudo-random key word;
C. means for dividing each said band into segments of different time duration in accordance with the pseudo-random key word;
D. means for compressing said segments in time and expanding them in frequency by a factor equal to the number of frequency bands into which the voice signal was divided; and
E. means for transmitting said time-compressed segments, the transmitted signal having substantially the same time-bandwidth product as the voice signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A privacy communication system digitizes a voice signal and divides the signal into different frequency bands or time segments and shifts the bands or segments in frequency and/or time under control of a continually changing pseudo-random key word to develop an encrypted transmitted signal having the same time/bandwidth product as the voice signal.
175 Citations
24 Claims
-
1. A privacy communication system comprising
A. means for splitting a voice signal into a selected number of frequency bands; -
B. means for generating a pseudo-random key word; C. means for dividing each said band into segments of different time duration in accordance with the pseudo-random key word; D. means for compressing said segments in time and expanding them in frequency by a factor equal to the number of frequency bands into which the voice signal was divided; and E. means for transmitting said time-compressed segments, the transmitted signal having substantially the same time-bandwidth product as the voice signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A privacy communication system comprising
A. means for dividing a voice signal into signal segments; -
B. means for expanding said segments in time and compressing them in frequency; C. means for generating a pseudo-random key word; D. means for shifting said segments in frequency and in time in accordance with the pseudo-random key word so as to stack said segments so that they span a frequency band which is approximately the same as the bandwidth of the voice signal; and E. means for transmitting the stacked segments, said transmitted signal having substantially the same time-bandwidth product as the voice signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
Specification