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GB638912A - Improvements in and relating to automatic frequency control in frequency-modulated carrier wave systems - Google Patents

Improvements in and relating to automatic frequency control in frequency-modulated carrier wave systems

Info

Publication number
GB638912A
GB638912A GB9130/47A GB913047A GB638912A GB 638912 A GB638912 A GB 638912A GB 9130/47 A GB9130/47 A GB 9130/47A GB 913047 A GB913047 A GB 913047A GB 638912 A GB638912 A GB 638912A
Authority
GB
United Kingdom
Prior art keywords
frequency
circuit
carrier
tuned
band
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
GB9130/47A
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.)
Maxar Space LLC
Original Assignee
Philco Ford Corp
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 Philco Ford Corp filed Critical Philco Ford Corp
Publication of GB638912A publication Critical patent/GB638912A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02—Automatic frequency control
    • H03J7/04—Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/002—Transmission systems not characterised by the medium used for transmission characterised by the use of a carrier modulation
    • H04B14/006—Angle modulation
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Multimedia (AREA)
  • Television Receiver Circuits (AREA)
  • Television Signal Processing For Recording (AREA)

Abstract

638,912. Automatic frequency control systems. PHILCO CORPORATION. April 3, 1947, No. 9130. Convention date, April 10, 1946. [Class 38 (iv)] [Also in Group XL (c)] An automatic frequency control system for frequency-modulated oscillators, particularly in television transmitters, in which the modulation comprises two components, the second of which (e.g. the synchronizing signal) varies the carrier over a band extending beyond the first, uses a frequency-error detector comprising a first circuit having a relatively flat response over the first band and a second circuit having a sharp response and tuned just beyond the second band, the two circuits being arranged so that the error signal produced depends on the carrier frequency corresponding to the synchronizing signal peak. The Figure shows an arrangement for converting a 75 me/s. F.M. television signal to 115 mc/s. for retransmission at a relay station. An output from the 115 mc/s. amplifier 3 is applied to a discriminator 7 comprising low Q circuit 8 tuned to a carrierfrequency within the vision component range and a high Q circuit 17 inductively coupled to the first circuit, tuned just beyond the carrier frequency corresponding to the synchronizing signal peak. The two halves of the discriminator are arranged in opposition and the crossover point adjusted so that changes in carrier amplitude are balanced out but a drift of the peak synchronizing carrier frequency towards the resonant frequency of the high Q circuit carries a large change of control voltage which acts on the frequency correcting deviator 5 to readjust the local oscillator frequency.
GB9130/47A 1946-04-10 1947-04-03 Improvements in and relating to automatic frequency control in frequency-modulated carrier wave systems Expired GB638912A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US660866A US2481902A (en) 1946-04-10 1946-04-10 Automatic frequency control circuit for frequency modulation television systems

Publications (1)

Publication Number Publication Date
GB638912A true GB638912A (en) 1950-06-21

Family

ID=24651283

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9130/47A Expired GB638912A (en) 1946-04-10 1947-04-03 Improvements in and relating to automatic frequency control in frequency-modulated carrier wave systems

Country Status (2)

Country Link
US (1) US2481902A (en)
GB (1) GB638912A (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2622146A (en) * 1945-12-15 1952-12-16 Rca Corp Automatic frequency control circuit for television
US2504663A (en) * 1947-11-12 1950-04-18 Gen Electric Automatic frequency control for television receivers
US2659813A (en) * 1950-02-11 1953-11-17 Bell Telephone Labor Inc Frequency modulation repeater
US2766320A (en) * 1952-11-12 1956-10-09 Motorola Inc Color television receiver with automatic frequency control
US3018325A (en) * 1958-03-20 1962-01-23 Westinghouse Electric Corp Television automatic frequency control apparatus
US3076055A (en) * 1960-04-04 1963-01-29 Ampex Recording and/or reproducing apparatus
US3421090A (en) * 1965-04-19 1969-01-07 Us Navy Control system for providing automatic frequency tracking of a carrier signal in an unsymmetrically frequency modulated video receiver system

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB469077A (en) * 1936-01-10 1937-07-12 James Robinson Improvements in or relating to wireless and like receivers
US2144235A (en) * 1937-01-15 1939-01-17 Rca Corp Automatic frequency control system
NL63344C (en) * 1938-09-20
US2296919A (en) * 1940-07-17 1942-09-29 Rca Corp Direct-current insertion
US2290517A (en) * 1940-08-02 1942-07-21 Hazeltine Corp Frequency-modulation television signal receiver
US2341649A (en) * 1941-05-23 1944-02-15 Rca Corp Frequency control
US2354827A (en) * 1941-05-23 1944-08-01 Rca Corp Frequency control
US2413913A (en) * 1942-10-29 1947-01-07 Rca Corp Frequency discriminator circuit

Also Published As

Publication number Publication date
US2481902A (en) 1949-09-13

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