US3715478A
Expired / Lapsed
US
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Secrecy facsimile system
Assignee: Thales SA
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Filing: 1970-07-31
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Granted: 1973-02-06
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Expires: 1990-07-31
Abstract
Abstract A system for secret communication is intended for transmitting successive sequences of n information digits, each sequence being separated from the following one by predetermined synchronization digits. The information digits are ciphered before the transmission, and the synchronization digits are transmitted in clear. The synchronization digits are used for synchronizing the ciphering at the transmission, and the deciphering at the reception.
Inventors
- 👤 J Vasseur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:21
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/44; H04N1/448; H04N1/4486
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
213 words
An arrangement for secret transmission of messages consisting of cyclically repeated sequences during which an information is transmitted alternating with fixed duration dead times serving as a reference comprising : means for generating a dead time signal at the end of each of said sequences : a ciphering system having respectively first and second inputs for receiving said message and said signal, and in said ciphering system : means coupled to said second input responsive to said signal for generating a characteristic signal during said dead times ; a clock having a triggering input coupled to said second input, for receiving said dead time signal for providing a predetermined number of pulses ; a key generator controlled by said clock, having an output ; a ciphering device having a first input coupled to said output of said key generator and a second input coupled to said first input of said ciphering system, and an output ; a switch having a first input coupled to said characteristic signal generating means, for receiving said characteristic signal, a second input coupled to said output of said ciphering device, and an output ; and means controlled by said clock, for alternately connecting said last mentioned output to said first and to said second input of said switch.
Claim 2
Dependent Claim
213 words
An arrangement for secret transmission of messages consisting of cyclically repeated sequences during which an information is transmitted alternating with fixed duration dead times serving as a reference comprising : means for generating a dead time signal at the end of each of said sequences : a ciphering system having respectively first and second inputs for receiving said message and said signal, and in said ciphering system : means coupled to said second input responsive to said signal for generating a characteristic signal during said dead times ; a clock having a triggering input coupled to said second input, for receiving said dead time signal for providing a predetermined number of pulses ; a key generator controlled by said clock, having an output ; a ciphering device having a first input coupled to said output of said key generator and a second input coupled to said first input of said ciphering system, and an output ; a switch having a first input coupled to said characteristic signal generating means, for receiving said characteristic signal, a second input coupled to said output of said ciphering device, and an output ; and means controlled by said clock, for alternately connecting said last mentioned output to said first and to said second input of said switch.
Claim 3
Dependent Claim
213 words
An arrangement for secret transmission of messages consisting of cyclically repeated sequences during which an information is transmitted alternating with fixed duration dead times serving as a reference comprising : means for generating a dead time signal at the end of each of said sequences : a ciphering system having respectively first and second inputs for receiving said message and said signal, and in said ciphering system : means coupled to said second input responsive to said signal for generating a characteristic signal during said dead times ; a clock having a triggering input coupled to said second input, for receiving said dead time signal for providing a predetermined number of pulses ; a key generator controlled by said clock, having an output ; a ciphering device having a first input coupled to said output of said key generator and a second input coupled to said first input of said ciphering system, and an output ; a switch having a first input coupled to said characteristic signal generating means, for receiving said characteristic signal, a second input coupled to said output of said ciphering device, and an output ; and means controlled by said clock, for alternately connecting said last mentioned output to said first and to said second input of said switch.
Claim 4
Dependent Claim
213 words
An arrangement for secret transmission of messages consisting of cyclically repeated sequences during which an information is transmitted alternating with fixed duration dead times serving as a reference comprising : means for generating a dead time signal at the end of each of said sequences : a ciphering system having respectively first and second inputs for receiving said message and said signal, and in said ciphering system : means coupled to said second input responsive to said signal for generating a characteristic signal during said dead times ; a clock having a triggering input coupled to said second input, for receiving said dead time signal for providing a predetermined number of pulses ; a key generator controlled by said clock, having an output ; a ciphering device having a first input coupled to said output of said key generator and a second input coupled to said first input of said ciphering system, and an output ; a switch having a first input coupled to said characteristic signal generating means, for receiving said characteristic signal, a second input coupled to said output of said ciphering device, and an output ; and means controlled by said clock, for alternately connecting said last mentioned output to said first and to said second input of said switch.
Claim 5
Dependent Claim
43 words
An arrangement, as claimed in claim 1, further comprising means for sampling and quantizing said message, said means being coupled between said first input of said ciphering system and said ciphering device, for producing successive sequences of pulses in synchronism with said clock.
Claim 6
Dependent Claim
174 words
A secrecy facsimile transmission system comprising: photoelectric means having an output for transducing successively into electric signals the lines of an image; means having an output for delivering a signal at the end of each line; a coding system; in said coding system a generator having an input for receiving said end line signal and delivering in response thereto a characteristic pulse sequence; means for sampling and quantizing said electric signals, for obtaining successive sequences of n pulses, at a predetermined frequency, n being a predetermined integer; a clock having a triggering input for receiving said end line signals, and generating, after each triggering, n pulses in synchronism with said pulses of said sequences of n pulses; a key generator controlled by said clock and having an output; a ciphering system coupled to said key generator, having an input for receiving said sequences of n pulses, and an output; a switch controlled by said clock and having two inputs respectively connected to said characteristic signal generator, and to said output of said ciphering system.
Claim 7
Dependent Claim
174 words
A secrecy facsimile transmission system comprising: photoelectric means having an output for transducing successively into electric signals the lines of an image; means having an output for delivering a signal at the end of each line; a coding system; in said coding system a generator having an input for receiving said end line signal and delivering in response thereto a characteristic pulse sequence; means for sampling and quantizing said electric signals, for obtaining successive sequences of n pulses, at a predetermined frequency, n being a predetermined integer; a clock having a triggering input for receiving said end line signals, and generating, after each triggering, n pulses in synchronism with said pulses of said sequences of n pulses; a key generator controlled by said clock and having an output; a ciphering system coupled to said key generator, having an input for receiving said sequences of n pulses, and an output; a switch controlled by said clock and having two inputs respectively connected to said characteristic signal generator, and to said output of said ciphering system.
Claim 8
Independent Claim
193 words
A system for decoding television signals comprising coded picture signals and line and field synchronizing signals in clear, said system comprising: an input for receiving said signals; a signal extractor coupled to said input and having two outputs for delivering respectively said line and field synchronization pulses; a first and a second phase discriminator having first inputs, respectively coupled to said outputs of said signal extractor circuit, second respective inputs, and respective outputs, a ponderator circuit having two inputs respectively coupled to said respective outputs of said phase discriminators, and an output; a local oscillator having a frequency equal to the line synchronization signal frequency, having a control input connected to said outpuT of said ponderator, a first and a second output; a frequency divider coupled to said first output of said oscillator to provide signals at said field frequency, said divider having an output coupled to said second input of said second discriminator; a clock connected to said output of said extractor delivering line pulses, and to said output of said delay line; a key generator controlled by said clock: and a deciphering device coupled to said input and said key generator.
Claim 9
Independent Claim
193 words
A system for decoding television signals comprising coded picture signals and line and field synchronizing signals in clear, said system comprising: an input for receiving said signals; a signal extractor coupled to said input and having two outputs for delivering respectively said line and field synchronization pulses; a first and a second phase discriminator having first inputs, respectively coupled to said outputs of said signal extractor circuit, second respective inputs, and respective outputs, a ponderator circuit having two inputs respectively coupled to said respective outputs of said phase discriminators, and an output; a local oscillator having a frequency equal to the line synchronization signal frequency, having a control input connected to said outpuT of said ponderator, a first and a second output; a frequency divider coupled to said first output of said oscillator to provide signals at said field frequency, said divider having an output coupled to said second input of said second discriminator; a clock connected to said output of said extractor delivering line pulses, and to said output of said delay line; a key generator controlled by said clock: and a deciphering device coupled to said input and said key generator.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |