| 4361729 |
Narrowband analog message privacy system |
| Nov-30-1982 |
A privacy system in which an analog information-bearing signal is linearly combined with a noiselike coding waveform to produce a composite waveform of unrecognizable, scrambled signal for transmission... |
| 4232194 |
Voice encryption system |
| Nov-4-1980 |
An apparatus and method of voice encryption uses segment swapping. Features of the invention include weighting the input time-function segments by a Hamming or Hanning Window function, before converting... |
| 4221931 |
Time division multiplied speech scrambler |
| Sep-9-1980 |
A privacy communication system in which increased security is provided in the scrambling of speech signals. Input speech is separated into a high frequency band and a low frequency band, and each band... |
| 4188506 |
Method and installation for masked speech transmission over a telephone channel |
| Feb-12-1980 |
A method and an installation for masked or scrambled speech transmission utilize a time-scrambling unit for dividing the speech band into at least two sub-bands, for delaying the one sub-band with respect... |
| 4172968 |
Electrical system |
| Oct-30-1979 |
1. In a secure communication system; means for producing an analog intelligence signal; means for limiting the amplitude of said signal; means for transforming portions of said amplitude limited signal... |
| 4160875 |
Security system |
| Jul-10-1979 |
A security system for use in homes, hotels, businesses, schools, streets, and other locations requiring a high degree of security but where it is important to insure the privacy of the protected individual. |
| 4149035 |
Method and apparatus for enciphering and deciphering audio information |
| Apr-10-1979 |
A method of, and apparatus for, enciphering and deciphering audio information which is subdivided into partial blocks along a time axis, the partial blocks being mutually interchangeable according to key... |
| 4133977 |
Voice scrambler using syllabic masking |
| Jan-9-1979 |
Voice signals are combined with a masking signal that changes frequencies between discrete frequencies at a selected rate and in a random manner. The combined voice spectrum and masking signal is frequency... |
| 4068094 |
Method and apparatus for the scrambled transmission of spoken information via a telephony channel |
| Jan-10-1978 |
A method of scrambling and unscrambling speech transmissions by first dividing the speech frequencies into two frequency bands and reversing their order by modulating the speech information, the width... |
| 4052565 |
Walsh function signal scrambler |
| Oct-4-1977 |
A digital speech scrambler system allowing for the transmission of scrambled speech over a narrow bandwidth by sequency limiting the analog speech in a low-pass sequency filter and thereafter multiplying... |
| 4020285 |
Voice security method and system |
| Apr-26-1977 |
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... |
| 4013837 |
Voice security method and system |
| Mar-22-1977 |
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... |
| 3995115 |
Speech privacy system |
| Nov-30-1976 |
The communication of confidential information is generally accomplished by transforming applied message waves into an unintelligible form prior to transmission. Such a transformation may be accomplished... |
| 3991271 |
Voice security method and system |
| Nov-9-1976 |
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... |
| 3985958 |
Secret telephony |
| Oct-12-1976 |
1. In secret telephony, means to analyze speech message waves into slowly varying currents representative of energy variations in respective portions of the speech frequency band, distributor means for... |
| 3978288 |
Method and apparatus for the secret transmission of speech signals |
| Aug-31-1976 |
Method and apparatus for enhancing the secret (confidential) transmission of voice (speech) type signals. The voice signals are encoded at a transmitter facility. Filling signals are inserted into breaks... |
| 3974336 |
Speech processing system |
| Aug-10-1976 |
A system of removing quantizing noise signals between words of an infinite-clipping speech system is disclosed. Speech signals are quantized in amplitude and in time without substantial loss of intelligibility.... |
| 3970791 |
Voice controlled disappearing audio delay line |
| Jul-20-1976 |
A delay line which disappears under voice control is comprised of a pluray of shift registers delays the incoming voice signal to permit transmission of the voice scrambler preamble. The delay is removed... |
| 3959592 |
Method and apparatus for transmitting and receiving electrical speech signals transmitted in ciphered or coded form |
| May-25-1976 |
A method of, and apparatus for, transmitting and receiving electrical speech signals transmitted in ciphered form, wherein at the transmitter end there are formed in sections or intervals from the speech... |
