FR2457615A1 - Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period - Google Patents

Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period

Info

Publication number
FR2457615A1
FR2457615A1 FR7912909A FR7912909A FR2457615A1 FR 2457615 A1 FR2457615 A1 FR 2457615A1 FR 7912909 A FR7912909 A FR 7912909A FR 7912909 A FR7912909 A FR 7912909A FR 2457615 A1 FR2457615 A1 FR 2457615A1
Authority
FR
France
Prior art keywords
bistable
output
time period
comparator
reset
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.)
Granted
Application number
FR7912909A
Other languages
French (fr)
Other versions
FR2457615B1 (en
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.)
SIGNALISATION CONTINENTAL
Original Assignee
SIGNALISATION CONTINENTAL
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 SIGNALISATION CONTINENTAL filed Critical SIGNALISATION CONTINENTAL
Priority to FR7912909A priority Critical patent/FR2457615A1/en
Publication of FR2457615A1 publication Critical patent/FR2457615A1/en
Application granted granted Critical
Publication of FR2457615B1 publication Critical patent/FR2457615B1/fr
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Television Systems (AREA)

Abstract

The time base is recovered from a composite video synchronisation signal to produce line synchronisation pulses for use in a teletext system. The output of the composite sync. circuit drives a phase locked loop to avoid disturbance to the image quality. A D-type bistable (1) receives the composite video sync. signal (V) at its clock input. The Q-output is applied to a phase locked loop (2) and to an integrator (3) which produces a sawtooth waveform which is compared with a threshold signal (5) by a comparator (7). The comparator output presets the bistable after a time period. The Q-bar output is connected to a similar integrator (10) and comparator (14) to reset the bistable after a time period. The time periods produced by the comparators provide a window for the line synchronisation signal.
FR7912909A 1979-05-21 1979-05-21 Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period Granted FR2457615A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7912909A FR2457615A1 (en) 1979-05-21 1979-05-21 Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7912909A FR2457615A1 (en) 1979-05-21 1979-05-21 Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period

Publications (2)

Publication Number Publication Date
FR2457615A1 true FR2457615A1 (en) 1980-12-19
FR2457615B1 FR2457615B1 (en) 1984-11-16

Family

ID=9225697

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7912909A Granted FR2457615A1 (en) 1979-05-21 1979-05-21 Recovery of time base for teletext system - uses PLL at output of bistable circuit, with counter to reset bistable after time period

Country Status (1)

Country Link
FR (1) FR2457615A1 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2737749A1 (en) * 1977-08-22 1979-03-01 Siemens Ag Interference pulse suppression circuit - detects pulses and replacement synchronisation pulses are applied to amplitude filter

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2737749A1 (en) * 1977-08-22 1979-03-01 Siemens Ag Interference pulse suppression circuit - detects pulses and replacement synchronisation pulses are applied to amplitude filter

Also Published As

Publication number Publication date
FR2457615B1 (en) 1984-11-16

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Legal Events

Date Code Title Description
ST Notification of lapse