GB668197A - Improvements in or relating to thermionic valve amplifiers suitable for television apparatus - Google Patents

Improvements in or relating to thermionic valve amplifiers suitable for television apparatus

Info

Publication number
GB668197A
GB668197A GB1937949A GB1937949A GB668197A GB 668197 A GB668197 A GB 668197A GB 1937949 A GB1937949 A GB 1937949A GB 1937949 A GB1937949 A GB 1937949A GB 668197 A GB668197 A GB 668197A
Authority
GB
United Kingdom
Prior art keywords
diode
condenser
distortion
grid
component
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
GB1937949A
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.)
ROBERT HYLTON KIRKNESS
General Electric Co PLC
Original Assignee
ROBERT HYLTON KIRKNESS
General Electric Co PLC
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 ROBERT HYLTON KIRKNESS, General Electric Co PLC filed Critical ROBERT HYLTON KIRKNESS
Priority to GB1937949A priority Critical patent/GB668197A/en
Priority to FR1029563D priority patent/FR1029563A/en
Publication of GB668197A publication Critical patent/GB668197A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/16—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level
    • H04N5/165—Circuitry for reinsertion of dc and slowly varying components of signal; Circuitry for preservation of black or white level to maintain the black level constant

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Picture Signal Circuits (AREA)

Abstract

668,197. Television. GENERAL ELECTRIC CO., Ltd., and KIRKNESS, R. H. July 24, 1950 [July 22, 1949], No. 19379/49. Class 40 (iii). In a conventional D.C. restoration circuit comprising a diode, condenser and resistance combination, distortion of the restored D.C. component, due to the inherent resistance of the circuit when the diode is conducting, is corrected by means of a compensating voltage injected in series with the diode. This distortion, which is manifest as a finite delay in restoring the D.C. component at the grid 10 of a valve 5, Fig. 2, (forming the output stage of a television amplifier) due to the timeconstant of condenser 11 and the inherent resistance of the D.C. restoring-diode 17 when it conducts during synchronizing intervals, is corrected by developing across condenser 22, which is connected in series with the diode 17, a voltage derived from the cathode resistance 12 which is of opposite phase to that at grid 10 and of an amplitude, determined by potentiometer 19, such as to compensate for the distortion. In order to prevent additional distortion of the reinserted D.C. component, caused by a rise in the potential of the grid during frame synchronizing periods (due to the difference in duration of the line and frame synchronizing signals), a further diode 32, Fig. 4, is arranged to supply a further compensating signal to condenser 22.
GB1937949A 1949-07-22 1949-07-22 Improvements in or relating to thermionic valve amplifiers suitable for television apparatus Expired GB668197A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1937949A GB668197A (en) 1949-07-22 1949-07-22 Improvements in or relating to thermionic valve amplifiers suitable for television apparatus
FR1029563D FR1029563A (en) 1949-07-22 1950-07-21 Thermionic valve amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1937949A GB668197A (en) 1949-07-22 1949-07-22 Improvements in or relating to thermionic valve amplifiers suitable for television apparatus

Publications (1)

Publication Number Publication Date
GB668197A true GB668197A (en) 1952-03-12

Family

ID=10128373

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1937949A Expired GB668197A (en) 1949-07-22 1949-07-22 Improvements in or relating to thermionic valve amplifiers suitable for television apparatus

Country Status (2)

Country Link
FR (1) FR1029563A (en)
GB (1) GB668197A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0625849A1 (en) * 1993-05-19 1994-11-23 STMicroelectronics S.A. Black level setting device for a video signal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0625849A1 (en) * 1993-05-19 1994-11-23 STMicroelectronics S.A. Black level setting device for a video signal
FR2705520A1 (en) * 1993-05-19 1994-11-25 Sgs Thomson Microelectronics Device for adjusting the black level of a video signal.
US5510854A (en) * 1993-05-19 1996-04-23 Sgs-Thomson Microelectronics, S.A. Device for adjusting the black level of a video signal

Also Published As

Publication number Publication date
FR1029563A (en) 1953-06-03

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