Kenneth E Heizer

US Patent:

40202852, Apr 26, 1977

Filed:

Jan 29, 1975

Appl. No.:

5/545084

Inventors:

Kenneth M. Branscome - Dallas TX
William M. Feath - Irving TX
George E. Goode - Richardson TX
Kenneth W. Heizer - Dallas TX
Barrie O. Morgan - Dallas TX

Assignee:

Datotek, Inc. - Dallas TX

International Classification:

H04K 104

US Classification:

179 15R

Abstract:

The specification discloses a voice scrambler technique wherein a voice signal is split into a plurality of discrete frequency sub-bands. A random code generator generates a randomized sequence of digital signals. A preselected first portion of each of the digital signals is utilized to control the rearrangement of the order of the frequency sub-bands according to a limited subset of all possible combinations of rearrangements of the frequency sub-bands. The limited subset is chosen to include only the most unintelligible of the possible combinations of rearrangements of the frequency sub-bands. A preselected second portion of each of the digital signals is utilized to control the random inversion of one of the frequency sub-bands. The rearranged and inverted frequency sub-bands are then transmitted over a conventional voice communication line to a similar voice scrambler unit which operates in synchronism to rearrange and invert the frequency sub-bands to the original state in order to render the voice signal intelligible. The system includes a unique synchronism technique which automatically compensates for time delays in transmission and which allows tolerance of transmission errors.

US Patent:

39912710, Nov 9, 1976

Filed:

Jan 29, 1975

Appl. No.:

5/545083

Inventors:

Kenneth M. Branscome - Dallas TX
William M. Feath - Richardson TX
George E. Goode - Richardson TX
Kenneth W. Heizer - Dallas TX
Barrie O. Morgan - Dallas TX

Assignee:

Datotek, Inc. - Dallas TX

International Classification:

H04L 900

US Classification:

178 695R

Abstract:

The specification discloses a voice scrambler technique wherein a voice signal is split into a plurality of discrete frequency sub-bands. A random code genertor generates a randomized sequence of digital signals. A preselected first portion of each of the digital signals is utiized to control the rearrangement of the order of the frequency sub-bands according to a limited subset of all possible combinations of rearrangements of the frequency sub-bands. The limited subset is chosen to include only the most unintelligible of the possible combinations of rearrangements of the frequency sub-bands. A preselected second portion of each of the digital signals is utilized to control the random inversion of ones of the frequency sub-bands. The rearranged and inverted frequency sub-bands are then transmitted over a conventional voice communication line to a similar voice scrambler unit which operates in synchronism to rearrange and invert the frequency sub-bands to the original state in order to render the voice signal intelligible. The system includes a unique synchronism technique which automatically compensates for time delays in transmission and which allows tolerance of transmission errors, with the randomized signal generator being rapidly stepped prior to initial transmission to generate a prime word, the rapid advancement serving to compensate for transmission path delay.

US Patent:

40138372, Mar 22, 1977

Filed:

Jan 29, 1975

Appl. No.:

5/545082

Inventors:

Kenneth M. Branscome - Dallas TX
William M. Feath - Irving TX
George E. Goode - Richardson TX
Kenneth W. Heizer - Dallas TX
Barrie O. Morgan - Dallas TX

Assignee:

Datotek, Inc. - Dallas TX

International Classification:

H04K 102

US Classification:

179 15S

Abstract:

The specification discloses a voice scrambler technique wherein a voice signal is split into a plurality of discrete frequency sub-bands. A random code generator generates a randomized sequence of digital signals. A preselected first portion of each of the digital signals is utilized to control the rearrangement of the order of the frequency sub-bands according to a limited subset of all possible combinations of rearrangements of the frequency sub-bands. The limited subset is chosen to include only the most unintelligible of the possible combinations of rearrangements of the frequency sub-bands. A preselected second portion of each of the digital signals is utilized to control the random inversion of ones of the frequency sub-bands. The rearranged and inverted frequency sub-bands are then transmitted over a conventional voice communication line to a similar voice scrambler unit which operates in synchronism to rearrange and invert the frequency sub-bands to the original state in order to render the voice signal intelligible. The system includes a unique synchronism technique which automatically compensates for time delays in transmission and which allows tolerance of transmission errors.