GB553381A - Improvements in television systems - Google Patents

Improvements in television systems

Info

Publication number
GB553381A
GB553381A GB15239/41A GB1523941A GB553381A GB 553381 A GB553381 A GB 553381A GB 15239/41 A GB15239/41 A GB 15239/41A GB 1523941 A GB1523941 A GB 1523941A GB 553381 A GB553381 A GB 553381A
Authority
GB
United Kingdom
Prior art keywords
diode
signals
resistance
grid
voltage
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
GB15239/41A
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.)
Marconis Wireless Telegraph Co Ltd
BAE Systems Electronics Ltd
Original Assignee
Marconis Wireless Telegraph Co Ltd
Marconi 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 Marconis Wireless Telegraph Co Ltd, Marconi Co Ltd filed Critical Marconis Wireless Telegraph Co Ltd
Publication of GB553381A publication Critical patent/GB553381A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00Details of television systems
    • H04N5/14Picture signal circuitry for video frequency region
    • H04N5/20Circuitry for controlling amplitude response
    • H04N5/202Gamma control

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Microwave Amplifiers (AREA)
  • Picture Signal Circuits (AREA)

Abstract

553,381. Television. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Nov. 26, 1941, No. 15239. Convention date, Nov. 27, 1940. [Classes 40 (iii) and 40 (v)] A television transmission circuit comprises an etectron discharge device 7 receiving on its control grid 5 signals including picture signals, blanking signals, and a reference voltage, a rectifier 25 in the output circuit of the electron discharge device, and means for applying a predetermined bias to the rectifier so that the signals passed are only those in one direction of polarity from a predetermined value. In the circuit shown in Fig. 1, the image signals are generated in a camera 1 supplied with synchronizing and blanking signals from a generator 9. The signals are amplified by an amplifier 3 and passed to the grid 5 of the electron device 7 through a condenser 8, which also transmits a blanking signal from the generator 9. This generator also supplies the blanking signal to a D.C. insertor circuit 11 which applies a reference bias voltage to the grid 5 of the electron device 7. The anode 17 of the electron device 7 and the cathode 23 of the diode 25 are connected to B+ through an adjustable resistance 21 in series with a fixed resistance 19. The screen grid 15 of the electron device 7 is connected to the same voltage source by the resistance 33. The anode 27 of the diode 25 is also connected to the same source of voltage through a resistance 35 in series with the resistance 33. The junction of the resistances 33, 35 is connected to a voltage regulator comprising a valve 37 in parallel with a condenser 39 and a resistance 41. The output is taken from the anode 27 of the diode to an amplifier 29 followed by a transmitter 31. In a modification, Fig. 4, a second diode 43 is added in the reverse direction in parallel with the diode 25, and an auxiliary valve 53 is inserted in the circuit of the diode 25 to act as a variable impedance which may be set to produce different amplification contrasts as for gamma control. In another modification, the second diode 43 is provided but the auxiliary valve 53 is omitted. Specifications 448,065 and 543,709 are referred to.
GB15239/41A 1940-11-27 1941-11-26 Improvements in television systems Expired GB553381A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US367324A US2326907A (en) 1940-11-27 1940-11-27 Television system

Publications (1)

Publication Number Publication Date
GB553381A true GB553381A (en) 1943-05-19

Family

ID=23446708

Family Applications (1)

Application Number Title Priority Date Filing Date
GB15239/41A Expired GB553381A (en) 1940-11-27 1941-11-26 Improvements in television systems

Country Status (2)

Country Link
US (1) US2326907A (en)
GB (1) GB553381A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE954338C (en) * 1950-11-09 1956-12-13 Philips Nv Circuit for automatic gain control in a television receiver
DE1045448B (en) * 1953-09-05 1958-12-04 Standard Elektrik Lorenz Ag Circuit arrangement to avoid the penetration of energy of the actual message content into the synchronous level range

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2426710A (en) * 1945-01-27 1947-09-02 Farnsworth Television & Radio Composite television signal generator
US2692299A (en) * 1948-12-11 1954-10-19 Westinghouse Electric Corp Image contrast intensifier
US2724738A (en) * 1949-07-02 1955-11-22 Pye Ltd Black and white signal limiter
FR2117909B1 (en) * 1970-12-16 1976-12-03 Fernseh Gmbh

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE954338C (en) * 1950-11-09 1956-12-13 Philips Nv Circuit for automatic gain control in a television receiver
DE1045448B (en) * 1953-09-05 1958-12-04 Standard Elektrik Lorenz Ag Circuit arrangement to avoid the penetration of energy of the actual message content into the synchronous level range

Also Published As

Publication number Publication date
US2326907A (en) 1943-08-17

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