GB715331A - Improvements in or relating to television receivers - Google Patents

Improvements in or relating to television receivers

Info

Publication number
GB715331A
GB715331A GB1862451A GB1862451A GB715331A GB 715331 A GB715331 A GB 715331A GB 1862451 A GB1862451 A GB 1862451A GB 1862451 A GB1862451 A GB 1862451A GB 715331 A GB715331 A GB 715331A
Authority
GB
United Kingdom
Prior art keywords
means
potential
derived
black level
pulses
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
GB1862451A
Inventor
Leslie Herbert Bedford
David John Fewings
Anthony Norman Heightman
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.)
BAE Systems Electronics Ltd
Marconis Wireless Telegraph Co Ltd
Original Assignee
BAE Systems Electronics Ltd
Marconis Wireless Telegraph Co 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 BAE Systems Electronics Ltd, Marconis Wireless Telegraph Co Ltd filed Critical BAE Systems Electronics Ltd
Priority to GB1862451A priority Critical patent/GB715331A/en
Publication of GB715331A publication Critical patent/GB715331A/en
Application status is Expired legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/44Receiver circuitry
    • H04N5/52Automatic gain control
    • H04N5/53Keyed automatic gain control

Abstract

715,331. Television. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. May 20, 1952 [Aug. 7, 1951], No. 18624/51. Class 40 (3). [Also in Group XL(c)] In a television receiver automatic gain control (A.G.C.) is obtained by clamping the black level at a pre-determined value and deriving an A.G.C. potential dependent upon the amplitude of the synchronizing pulses in the clamped signal. The composite demodulated signal is applied over an amplifier to the grid E of the picture-tube, via a blocking condenser C1. The black level is stabilized at earth potential by means of diodes D1, 2, which are biased to be non-conductive save during the " back-porch " period, the gating means comprising negative-going pulses derived from a winding L1 on the line output transformer. The gating pulses are suitably delayed by means of a time-delay network comprising inductance L2, condensers C2, 3 and terminating resistances R5, 6. The A.G.C. potential is derived in accordance with the synch. signal amplitude by means of a peak-rectifying diode D3, part only of the D.C. output being utilized by means of a potentiometer R7, 8. In an alternative embodiment, Fig. 2 (not shown) in which the picture tube is cathode modulated, the black level is stabilized at the grid of the video amplifier and the A.G.C. potential derived at this point.
GB1862451A 1951-08-07 1951-08-07 Improvements in or relating to television receivers Expired GB715331A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1862451A GB715331A (en) 1951-08-07 1951-08-07 Improvements in or relating to television receivers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1862451A GB715331A (en) 1951-08-07 1951-08-07 Improvements in or relating to television receivers
DEM14969A DE958121C (en) 1951-08-07 1952-07-31 Circuit for generating a fade control voltage in Fernsehempfaengern

Publications (1)

Publication Number Publication Date
GB715331A true GB715331A (en) 1954-09-15

Family

ID=10115656

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1862451A Expired GB715331A (en) 1951-08-07 1951-08-07 Improvements in or relating to television receivers

Country Status (2)

Country Link
DE (1) DE958121C (en)
GB (1) GB715331A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE535502A (en) * 1954-02-09

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE486285A (en) * 1947-12-13
BE492808A (en) * 1948-12-18

Also Published As

Publication number Publication date
DE958121C (en) 1957-02-14

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