GB548443A - Improvements in television and like transmission - Google Patents

Improvements in television and like transmission

Info

Publication number
GB548443A
GB548443A GB8996/41A GB899641A GB548443A GB 548443 A GB548443 A GB 548443A GB 8996/41 A GB8996/41 A GB 8996/41A GB 899641 A GB899641 A GB 899641A GB 548443 A GB548443 A GB 548443A
Authority
GB
United Kingdom
Prior art keywords
frequency
condensers
grids
circuit
signals
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
GB8996/41A
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 GB548443A publication Critical patent/GB548443A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/04—Systems for the transmission of one television signal, i.e. both picture and sound, by a single carrier
    • H04N7/045—Systems for the transmission of one television signal, i.e. both picture and sound, by a single carrier the carrier being frequency modulated
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H03C3/09—Modifications of modulator for regulating the mean frequency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/10—Angle modulation by means of variable impedance
    • H03C3/12—Angle modulation by means of variable impedance by means of a variable reactive element
    • H03C3/14—Angle modulation by means of variable impedance by means of a variable reactive element simulated by circuit comprising active element with at least three electrodes, e.g. reactance-tube circuit

Landscapes

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

Abstract

548,443. Frequency stabilization. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 16,1941, No. 8996. Convention date, July 17, 1940. [Class 38 (iv)] [Also in Groups XL and XXXVI] In carrier-wave frequency-modulation systems especially for the transmission of television signals, an extreme frequency is stabilized when the average intensity of the signals varies by means of a circuit which develops a voltage proportional to the amount by which the extreme frequency is exceeded and applies this voltage to frequency determining means to vary the mean frequency of the oscillations to bring their peaks to the desired value. As shown in Fig. 3, an oscillator 2 with a regenerative circuit 12 is coupled by condensers BC to reactance valve modulators 14, 141. The grids and anodes of these valves are coupled by phase shifting condensers 22, 221 and the cathodes are connected by condensers 23 231 to earth. Frequency modulation of the generated signals is accomplished by impressing video signals through a condenser 25 on the grids 18, 181 in phase. The modulated output is transmitted through amplifier and/or limiter stages 20 to a suitable transmitter and also to a limiter 50 leading to a resonant circuit 52 including a diode peak detector 56 having a sloping characteristic C, Fig. 2c. The diode is connected by a time-constant resistance-condenser circuit 62, 64 to the grid 71 of a direct current amplifier 73, the anode of which is connected by resistance 78 to the grids 18, 181 of the modulating valves 14, 141 to produce the desired stabilization. Specification 547,473, [Group XL], is referred to. Reference has been directed by the Comptroller to Specification 539,198.
GB8996/41A 1940-07-17 1941-07-16 Improvements in television and like transmission Expired GB548443A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US345895A US2296919A (en) 1940-07-17 1940-07-17 Direct-current insertion

Publications (1)

Publication Number Publication Date
GB548443A true GB548443A (en) 1942-10-09

Family

ID=23356982

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8996/41A Expired GB548443A (en) 1940-07-17 1941-07-16 Improvements in television and like transmission

Country Status (2)

Country Link
US (1) US2296919A (en)
GB (1) GB548443A (en)

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435736A (en) * 1941-02-13 1948-02-10 Zenith Radio Corp Frequency modulated picture receiver
US2436640A (en) * 1942-05-07 1948-02-24 Nils Georg Schonander Device for the frequency modulation of the resonant frequency of cavity resonators
US2430978A (en) * 1943-07-31 1947-11-18 Rca Corp Modulation limiter
US2502213A (en) * 1944-03-24 1950-03-28 Rca Corp Intelligence transmission system
BE473672A (en) * 1945-04-23
US2483438A (en) * 1945-04-23 1949-10-04 Standard Telephones Cables Ltd Frequency modulation system
US2622146A (en) * 1945-12-15 1952-12-16 Rca Corp Automatic frequency control circuit for television
US2481902A (en) * 1946-04-10 1949-09-13 Philco Corp Automatic frequency control circuit for frequency modulation television systems
US2552140A (en) * 1946-09-19 1951-05-08 Philco Corp Automatic frequency-control system for frequency-modulation television systems
FR958065A (en) * 1946-12-31 1950-03-03
US2588730A (en) * 1947-05-02 1952-03-11 Wayne R Johnson Method and apparatus for frequency response measurement
US2509789A (en) * 1947-06-05 1950-05-30 Raytheon Mfg Co Transmitter for frequency-modulated radio communication systems
US2592308A (en) * 1948-09-01 1952-04-08 Bell Telephone Labor Inc Nonlinear pulse code modulation system
ES187413A1 (en) * 1948-09-25 1949-05-01 Rca Corp A FREQUENCY STABILIZING SYSTEM
US2617923A (en) * 1949-08-31 1952-11-11 Kxok Inc Radio broadcasting system with selective program elimination
US2659813A (en) * 1950-02-11 1953-11-17 Bell Telephone Labor Inc Frequency modulation repeater
US2716152A (en) * 1950-03-28 1955-08-23 Emi Ltd Remote control for television camera
NL166448B (en) * 1951-01-03 Hartley Simon Ltd AERATOR.
US2674650A (en) * 1951-01-24 1954-04-06 Rca Corp Color television synchronizing system
GB702169A (en) * 1951-05-31 1954-01-13 Emi Ltd Improvements in or relating to electric control circuits
US2924703A (en) * 1957-07-12 1960-02-09 Itt Communication control system
US2989622A (en) * 1958-12-29 1961-06-20 Bell Telephone Labor Inc Hybrid sideband frequency modulation system
FR2260221B1 (en) * 1974-02-04 1980-01-11 Matra

Also Published As

Publication number Publication date
US2296919A (en) 1942-09-29

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