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GB2186768B - Video display unit with improved security - Google Patents

Video display unit with improved security

Info

Publication number
GB2186768B
GB2186768B GB8608104A GB8608104A GB2186768B GB 2186768 B GB2186768 B GB 2186768B GB 8608104 A GB8608104 A GB 8608104A GB 8608104 A GB8608104 A GB 8608104A GB 2186768 B GB2186768 B GB 2186768B
Authority
GB
United Kingdom
Prior art keywords
display unit
video display
improved security
security
improved
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB8608104A
Other versions
GB2186768A (en
Inventor
Richard C Marshall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DATA HOLKEN AB
EMC Datacare Ltd
Original Assignee
DATA HOLKEN AB
EMC Datacare Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DATA HOLKEN AB, EMC Datacare Ltd filed Critical DATA HOLKEN AB
Publication of GB2186768A publication Critical patent/GB2186768A/en
Application granted granted Critical
Publication of GB2186768B publication Critical patent/GB2186768B/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/06—Secret communication by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K3/00—Jamming of communication; Counter-measures
    • H04K3/80—Jamming or countermeasure characterized by its function
    • H04K3/82—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection
    • H04K3/827—Jamming or countermeasure characterized by its function related to preventing surveillance, interception or detection using characteristics of target signal or of transmission, e.g. using direct sequence spread spectrum or fast frequency hopping
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/16—Analogue secrecy systems; Analogue subscription systems
    • H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
    • H04N7/169—Systems operating in the time domain of the television signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K2203/00—Jamming of communication; Countermeasures
    • H04K2203/10—Jamming or countermeasure used for a particular application
    • H04K2203/14—Jamming or countermeasure used for a particular application for the transfer of light or images, e.g. for video-surveillance, for television or from a computer screen

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Multimedia (AREA)
  • Controls And Circuits For Display Device (AREA)
GB8608104A 1985-04-19 1986-04-03 Video display unit with improved security Expired GB2186768B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8510129 1985-04-19

Publications (2)

Publication Number Publication Date
GB2186768A GB2186768A (en) 1987-08-19
GB2186768B true GB2186768B (en) 1989-07-05

Family

ID=10577950

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8608104A Expired GB2186768B (en) 1985-04-19 1986-04-03 Video display unit with improved security

Country Status (1)

Country Link
GB (1) GB2186768B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2634085A1 (en) * 1988-07-06 1990-01-12 Radiotechnique Ind & Comm DEVICE FOR SCREENING OR UNLOCKING FOR A MAC TELEVISION SYSTEM

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB766619A (en) * 1954-03-10 1957-01-23 Zenith Radio Corp Improvements in or relating to subscription color television system
GB797517A (en) * 1953-10-16 1958-07-02 Sautier & Jaeger Improvements in and relating to line scanning time base for television receivers
EP0004798A2 (en) * 1978-04-12 1979-10-17 Data Recall Limited Video display control apparatus
GB2090507A (en) * 1980-12-31 1982-07-07 Mars Ltd Cathode ray tube display device
GB2095071A (en) * 1981-03-13 1982-09-22 Oak Industries Inc Video scrambling and descrambling means using frequency dependent delay means
GB2113940A (en) * 1981-04-28 1983-08-10 Elliott Bros Data transmission system
EP0149730A2 (en) * 1983-11-28 1985-07-31 International Business Machines Corporation CRT displays with variable format controls

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB797517A (en) * 1953-10-16 1958-07-02 Sautier & Jaeger Improvements in and relating to line scanning time base for television receivers
GB766619A (en) * 1954-03-10 1957-01-23 Zenith Radio Corp Improvements in or relating to subscription color television system
EP0004798A2 (en) * 1978-04-12 1979-10-17 Data Recall Limited Video display control apparatus
GB2090507A (en) * 1980-12-31 1982-07-07 Mars Ltd Cathode ray tube display device
GB2095071A (en) * 1981-03-13 1982-09-22 Oak Industries Inc Video scrambling and descrambling means using frequency dependent delay means
GB2113940A (en) * 1981-04-28 1983-08-10 Elliott Bros Data transmission system
EP0149730A2 (en) * 1983-11-28 1985-07-31 International Business Machines Corporation CRT displays with variable format controls

Also Published As

Publication number Publication date
GB2186768A (en) 1987-08-19

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20050403