GB605109A - Television receiving systems - Google Patents

Television receiving systems

Info

Publication number
GB605109A
GB605109A GB33906/45A GB3390645A GB605109A GB 605109 A GB605109 A GB 605109A GB 33906/45 A GB33906/45 A GB 33906/45A GB 3390645 A GB3390645 A GB 3390645A GB 605109 A GB605109 A GB 605109A
Authority
GB
United Kingdom
Prior art keywords
pulses
pulse
sound
signals
circuit
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
GB33906/45A
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.)
STC PLC
Original Assignee
Standard Telephone and Cables 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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB605109A publication Critical patent/GB605109A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00Television systems
    • H04N7/08Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band, e.g. by time division
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J3/00Time-division multiplex systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Television Systems (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

605,109. Television. STANDARD TELEPHONES & CABLES, Ltd. Dec. 14, 1945, No. 33906. Convention date, Aug. 25, 1944. [Class 40 (iii)] [Also in Group XL (c)] A television receiving system comprises means adapted to receive a desired one of a plurality of programmes, each of which is represented by vision signals transmitted by modulation of a corresponding one of a plurality of carrier waves of different frequencies, the necessary synchronising signals, which are common to all vision programmes, being transmitted on a carrier wave of frequency different from that of any of the other carrier waves. The carrier wave with the synchronising signals may also carry modulated pulses representing the sound signals for the several vision programmes. The receiver 11, Fig. 1, includes antennµ 12, 13, directively positioned with respect to the transmitting antenna 5 and adapted to receive respectively the video and multi-channel carriers which after amplification and detection in the tunable amplifiers 14, 15 and detectors 16, 18 have a wave form and pulse train such as a, b, Fig. 2, respectively. The video wave-form comprising vision signals 10 and horizontal and vertical blanking pulses HB, VB together with appropriate synchronising pulses are utilized to reproduce the image in the picture reproducer 17 according to known methods. The synchronising pulses are derived from the pulse train b, Fig. 2, in the pulse width discriminator 19, shown in detail in Fig. 3, in which the pulse train is applied to a limit clipping and inverting valve 20, the output of which shock excites the L.C. circuit 21, which is tuned to a resonant frequency equal to half the period of the pulse V, Fig. 2, so that during .the occurrence of the latter pulses the oscillatory effects produced in circuit 21 by the leading and trailing edges of these pulses add together to produce an oscillation such as 34, 39, (curve c, Fig. 2), whereas, during the occurrence of the narrower pulses H, the additive effect produces an average oscillation such as 34, 39, Fig. 2, and, the still narrower sound pulses 1, 2, 3, oscillations such as 40. Both oscillations are damped out after one complete period due to the action of valve 22, which is shunted across circuit 21 and supplied with a negative blocking pulse during 'the occurrence of the pulses Hand V. The output waveform c, Fig. 2, is clipped at levels 31, 45, Fig. 2, in clippers 30, 32 from which horizontal and vertical synchronising pulses d, e, Fig. 2, are produced in the pulse shapers 42, 46, Fig. 1. In order to select the sound channel corresponding to the desired vision signals the pulse train b, Fig. 2, is applied to the channel selecting mixer 49 which permits the passage of signal pulses only when an additional pulse, such as 52, f, Fig. 2, is simultaneously applied. This pulse is derived from the horizontal pulse shaper 42 and after further shaping in 51 is applied to the channel selecting mixer 49 via a variable delay device 53, which retards the pulses 52 by an amount sufficient to cause them to coincide with the occurrence of the desired sound pulse 1, 2 or 3, Fig. 2, and, consequently to raise their level above the clipping level 54 of the limit amplifier 55. This amplifier is also supplied with pulses d, Fig. 2, from the horizontal pulse shaper 42 which act as reference pulses from which the displacement of the sound pulses may be measured to effect translation of this displacement to amplitude variations in the demodulator 56 for application to the sound reproducer 58 via the filter 59. A suitable circuit for the demodulator is shown in Fig. 4, and comprises a valve 62 in the screengrid circuit of which is a resonant circuit 64 tuned to provide a shock-excited damped wave, the peaks of which pass through the pulse position points of h, Fig. 2, in the absence of modulation. When, due to modulation, the sound pulses are displaced from this latter position, their occurrence coincides with the linear portion of the shock-excited wave, thereby causing the oscillatory swing to vary in amplitude by an amount proportional to their displacement from their zero-modulation position, this position being determined by the reference pulse 43a, Fig. 2, which sets the clipping level of valve 62 at 76, Fig. 2, and produces the pulse train j, the envelope 77 of which defines the envelope of the original modulating signals. Specification 597,461 is referred to.
GB33906/45A 1944-08-25 1945-12-14 Television receiving systems Expired GB605109A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US551203A US2477625A (en) 1944-08-25 1944-08-25 Multiplex television and pulse modulated sound system

Publications (1)

Publication Number Publication Date
GB605109A true GB605109A (en) 1948-07-15

Family

ID=24200279

Family Applications (1)

Application Number Title Priority Date Filing Date
GB33906/45A Expired GB605109A (en) 1944-08-25 1945-12-14 Television receiving systems

Country Status (5)

Country Link
US (1) US2477625A (en)
BE (1) BE474059A (en)
ES (1) ES175406A1 (en)
FR (1) FR938666A (en)
GB (1) GB605109A (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563448A (en) * 1951-08-07 Subscription type signaling system
US2628274A (en) * 1944-06-27 1953-02-10 John H Homrighous Multiplex television system
US2543015A (en) * 1945-09-27 1951-02-27 Standard Telephones Cables Ltd Receiver circuit
US2535547A (en) * 1946-09-10 1950-12-26 Rca Corp Telemetering system
US2647944A (en) * 1946-11-26 1953-08-04 American Optical Corp Single carrier transmission of sound and video signals
US2510046A (en) * 1947-04-18 1950-05-30 Zenith Radio Corp Radio-wire signaling system
US2567545A (en) * 1948-09-30 1951-09-11 Zenith Radio Corp Subscription-type television receiver
US2551068A (en) * 1948-10-05 1951-05-01 Zenith Radio Corp Coded-sound, television receiver
US3178515A (en) * 1961-03-27 1965-04-13 Gen Signal Corp Plural modulation communication system
US7912376B2 (en) * 2007-09-28 2011-03-22 Rockwell Automation Technologies, Inc. Non-interfering transmitted-beam pairs

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB322025A (en) * 1928-09-17 1929-11-28 Graham Amplion Ltd Improvements in and relating to systems for the electrical transmission of photographs and the like and for television
US1975055A (en) * 1929-03-25 1934-09-25 Rca Corp Television system
GB397681A (en) * 1931-09-25 1933-08-31 Manfred Von Ardenne Arrangement for transmitting topical occurrences to a television sender
US2089639A (en) * 1933-04-08 1937-08-10 Rca Corp Intelligence transmission
GB421937A (en) * 1933-11-06 1935-01-02 Suddeutsche Telefon App Kabel Improvements in and relating to picture assembling in television receivers
DE758151C (en) * 1936-05-12 1954-02-22 Telefunken Gmbh Arrangement for reportage television stations that are synchronized by the main station to which they deliver their programs
US2231971A (en) * 1938-04-06 1941-02-18 Nat Television Corp Synchronizing system for picture transmission
US2198969A (en) * 1938-08-10 1940-04-30 Hazeltine Corp Television scanning system
US2282046A (en) * 1939-09-01 1942-05-05 Rca Corp Multiplex signaling system
CH230167A (en) * 1942-01-26 1943-12-15 France Henri De Method for the transmission of remote signals and installation for the implementation of this method.
US2329339A (en) * 1942-03-07 1943-09-14 Rca Corp Electrical circuit
US2391776A (en) * 1943-05-29 1945-12-25 Rca Corp Intelligence transmission system
BE477481A (en) * 1944-05-05
BE465456A (en) * 1944-07-17
FR954531A (en) * 1944-07-29 1950-01-03
US2416330A (en) * 1944-08-07 1947-02-25 Standard Telephones Cables Ltd Multichannel receiving system
US2408077A (en) * 1944-08-25 1946-09-24 Standard Telephones Cables Ltd Multichannel system
BE467470A (en) * 1944-08-25

Also Published As

Publication number Publication date
ES175406A1 (en) 1946-12-01
BE474059A (en)
US2477625A (en) 1949-08-02
FR938666A (en) 1948-10-21

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