US2227002A - Television transmission method - Google Patents

Television transmission method Download PDF

Info

Publication number
US2227002A
US2227002A US57870A US5787036A US2227002A US 2227002 A US2227002 A US 2227002A US 57870 A US57870 A US 57870A US 5787036 A US5787036 A US 5787036A US 2227002 A US2227002 A US 2227002A
Authority
US
United States
Prior art keywords
tube
cathode
synchronizing
impulses
image
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 - Lifetime
Application number
US57870A
Other languages
English (en)
Inventor
Schlesinger Kurt
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.)
LOEWE RADIO Inc
Original Assignee
LOEWE RADIO Inc
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 LOEWE RADIO Inc filed Critical LOEWE RADIO Inc
Application granted granted Critical
Publication of US2227002A publication Critical patent/US2227002A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H04N5/067—Arrangements or circuits at the transmitter end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/08—Separation of synchronising signals from picture signals

Definitions

  • a disadvantage of this method exists atwthe transmission end.
  • a certain amplitude range mustv be reserved solelyfor the synchronisation signals.
  • the transmitter therefore, cannot be -controlled fully by the image signals alone.
  • two-thirds of the aerial current at the most can be employedfor the image signals, and the remaining one-thirdl must be reserved for the synchronisation signals.
  • strongY atmospheric interferences are always able 4to actuate the synchron-is'ing apparatus when their volume of sound exceeds the threshold of response of the filter.
  • the present invention eliminates these disadvantages by the time blocking method.
  • the fundamental idea of this method resides Vin the following: Between the image-signal receiver and the synchronisation terminals of l the scanning apparatus there is provided an amplitude filter of a particular kind, lthe surge value of which is variable.
  • This filter as described in the following, is completely blocked for 90% of the ⁇ line period (blocking phase). During this period it 45 cannot vbe passed even by the most powerful reception amplitude, and no interferences are able t inuence the synchronisation. It is only just before the end of the line is 4reached that the surge value Iof the lter is differently adjusted.
  • the filter is so biassed that it may now be penetrated by signals of normal recept-ion intensity.
  • Figures la and 1h show image areas for producing? picture ⁇ and synchronizingsignals
  • ⁇ Figure 2a shows a curve indicating the relationship between light intensity and antenna current orcarrier amplitude
  • Figure 2b shows a wave form of the combined picture and synchronizing signals
  • FIG. 3 shows one form of the present invention
  • Figure 4- shows graphically the voltage variations which occur in the circuit diagram ⁇ shown in FigurelB.
  • Fig. 1a explains these conditionsin detail. It is assumed that an image with the image area l is given in positive fashion, for example as positive film.
  • the transmitter is modulated with thisimage content in suchv fashion that a white point inthe image corresponds witha large aerial current, whilst a deep black point in the image causes the aerial current to disappear.
  • the characteristic 2 of the transmitter in Fig. ⁇ 2a represents the connection between ⁇ the light intensity of the image H and the intensity of the aerial current-i.
  • vThe time sections l, 8, etc. correspond in each case with a line peri-od.
  • the scanning image point moves over the double edge 5/6.
  • the edge signal commences with an intensity Hs corresponding with the inner margin lighted with this intensity in Fig. 2b.
  • the edge signal terminates with the intensity 0 at that moment when the scanning image point passes into the outer margin 6 in Fig. la, because in this phase a lighting of any kind does not occur.
  • TheV time at which this change-over from H5 to 0 takes place is designated tz in Fig. 2b.
  • tz represents: ignition moment.
  • Fig. 3 shows an example of a receiver connection for receiving a transmission of thedescribed kind.
  • a heterodyne receiver is supposed; the final tube of the intermediate frequency amplifier is designated 9.
  • This tube is coupled with the twin grid detector tube il by means of the transformer I0.
  • the conductivity of this tube decreases andthe anode gets more positive when the transmitted intensity increases.
  • the anode is connected tothe control grid I6 of Vthe television tube I1 and takes care of the modulation of the electronic rayv preceding from the cathode I8 of the television tube.
  • the amplitude filter and time blocking devices according to the invention is the tube I4. Its cathode I5 is directly connected to the anode of the detector tube I I, its anode I9 to a counterpotential variable by means of the potentiometer 20.
  • and 22 which sepa-rate the synchronization impulses according to their timer duration, whereby the transformer 2
  • the relaxation oscillators or beam deflection generators are shown schematically at 36 and 3'I since any satisfactory oscillator may be used. An example of s uch an oscillator is to be found in the U. S. patent to Tolson No. 1,999,378.
  • the feature of the present invention is the function of the twin grids 23, 213' of which 23 is associated withthe vertical or frame oscillator while 23' is associated with thehorizontal or line oscillator. They attend tothe time blocking ofthe amplitude lter 4I4 in thev following manner:
  • control grid 23 is connected to the output of the/relaxation oscillator for deecting the cathode ray towards the synchronization edge of the image.
  • this plate assumes inthe deflecting phase a positive D.C. potential of continuously increasingnamount.
  • This potential lis added to the bias 28 imparted to the grid. via the leakage resistance 21.
  • the negative bias 28 is selected of such value that mere- -mately 10% of the line period 33. ⁇ relaxation potential always remains constant, as
  • Fig. 4 shows the temporal course of the line relaxation oscillation such as passes from the left hand image edge 29 to the right h-and image edge 3
  • the bias is designated 3l, and is selected to be of such extent that the waiting phase, viz., the time section 32, amounts to approxi- Since the this is identical with the constant size of the image field in the receiver, and since the bias 28'is also a constant D.C. potential, the length of the waiting phase 32 may be adjusted to be constant.
  • l*The curve 34 shows .the course adopted by .the grid potential of the tube I4 by the action l of this coupling with the plate circuit.
  • the grid bias does not continue to increase without limitation, but always remains at the most approximately l volt more positive than the particular cathode potential I5. Although, therefore, there is a weak positive grid-cathode bias during the waiting phase no current occurs in the anode circuit IIJ/20. Wearenow in the scanning period-which may readilyv be attained by adjustment of the frequency of the free relaxation oscillation at the receiverover the infner edge of the edge signal (edge 5, intensity H5, Figs. 1 and 2). ⁇ During this period the detector tube II is excited.
  • the cathode I5 is biassed positively in relation to the anode, and although the control grid 23 is in a condition permitting passageno anode current is able to occur. It is only at the ignition point tz (Fig. 2b) when the scanning pointpasses over to the outer margin 6, that the aerial current disappears. The cathode then becomes negative in relation to the anode, and since moreover the grid is weakly positive in relation to the cathode a synchronising current impulse now passes through ithe filter I4. In this way, however, the image point is thrown to the opposite side of the image, i. e., the deilecting plate 25a again becomes negative to the extent of a few -hundred volts. The grid 23 of the amplitude filter I4 is again blocked in such'fashion that every kind of connection is interrupted between receiving element and synchronising element.
  • Theduration of the waiting phase mustfbe equal to or. greater than the scanning period for ⁇ the marginal zone of the image. If this condition is not observed and if the Waiting phase is toosmall, the adjustment of the synchronisation is v,rendered more diiiicult. Otherwise the adjustment is no more difficult than upon reception of the transmissions heretofore. i
  • a coupling may be performed withthe vertical plates of the television tube I1.
  • a picture reproducing cathode ray tube including a cathode ray beam generating means, a beam modulating electrode and horizontal and vertical 'electronl beam-deflecting means, means for impressing the ⁇ picture signals and synchronizing impulses ⁇ upon the beam modulating electrode of the cathode ray tube, a synchronizing signal separator tube includinga cathode, an output electrode and a pair vof control electrodes, means forimpressing the produced series of picture and synchronizing signal
  • .fi-television receiver for receivingia carrier modulated by picture signals and synchronizing ⁇ impulses comprislnga detector to demodulate the ⁇ carrier Vto :produce a series of picture signals and synchronizing'impulses, a Vpicture reproducing cathode rayf tube including a cathode ray beam generating means, a beam modulating electrode and electron beam deilecting means, means for .impressing the produced series of picture signals and synchronizing impulses upon the beam mod- -ulating electrode of the cathode ray tube, a synchronizing, signal separator tube including a cathode, .an outputelectrode anda control electrode, means for impressing the synchronizing signal impulses on the cathode of the separator tube, .means coupled to the output electrode of said .tube for producing beam deection voltage variations for controlling the electron beam defleetingl means ina predetermined operational .cycle in'response to the synchronizing impulse
  • a television receiver for receiving a carrier ⁇ modulated by picture signals and synchronizing :signals and the synchronizing impulses on the Jcathodeof the separator tube, means coupled to Vthe output electrode of said tube for producing beam deflection voltage variations for energizing the horizontal and vertical beam deflecting .means in response to the synchronizing impulses,
  • control electrodes means for biasing the control electrodes at a predeterminedpotential with respect to the cathode of the separator tube and means for coupling the rpair of control electrodes to the horizontal and V,vertical beam deecting means respectively,
  • ⁇ the separator tube is conditioned for conduction only in accordance with the time of receipt of synchronizing signalling impulses.
  • a television receiver wherein a series of picturesignals and synchronizing impulses are used to produce a television picture comprising a cathode ray tube, means for generating a beam of electrons in the tube, means for modulating the beam of electrons and means for deflecting the beam of electrons in substantially mutually perpendicular directions, deflection voltage generating meansr for energizing the beam deflecting means, a discharge tube including a cathode, a control* electrode and an anode, means for impressing the picture signals and synchronizing impulses upon the cathode of said tube, synchrolnizing impulse' responsive means connected to the .anode of said tube for controlling the deliection voltage'generating means, means .for biasing the 5.
  • A'television receiver wherein a series of pic-I ture and synchronizing signal impulses are used to produceand synthesize a television picture comprising afcathode ray tube, means for generating a beam of electrons in the tube, means for modulating thebeam of 4electrons under the control of the said signals and means ⁇ for ,defiecting the beam of electrons in mutually perpendicular directions, means for generating electrical energy for energizing the beam deflecting means, a discharge tube includingna cathode, a control electrode and an anode, means for impressing at least the synchronizing signal impulses upon the cathode of said tube, means connectedrtothe anode of said.
  • a television receiver wherein a series of picture signals and synchronizing impulses are used to produce a ⁇ television picture comprising a cathode ray tube, means for generating a beam of electrons in the tube, means for modulating the'beam of electrons and means for deflecting the beam of electrons in substantially mutually perpendicular directions, deflection energygenerating means for energizing the beam deflecting means, a discharge tube including a cathode, a control electrode and an anode, means for impressing the synchronizing impulses between the cathode and control electrode of said tube, synchronizing signal impulse responsive means connected to the anode of said tube for controlling the deflection energy generating means, means for biasing the control ⁇ electrode to a predetermined negative potential relative to the cathode to normally prevent conduction in the tube, and meansA including an electron storage means vfor coupling the control electrode to the deiiection energy generating means whereby the bias on said tube is reduced at a time immediately prior to the
  • a television system wherein a series of picture signals and synchronizing impulses are used ⁇ to produce a television image including a picture .producing cathode ray tube, means in said tube ing impulses for controlling the deflection energy generating means, means for applying the series of picture signals and synchronizing impulses between the cathode and the control electrode of said tube, means for biasing the control electrode at a predetermined potential vrelative to the cathode to normally prevent the flow ofY electronic current through the tube, and
  • deflection energy generating means whereby the vbias 4on said tube is so reduced as to render the tube responsive to the synchronizing impulses only during a time interval approximating the time of arrival of each synchronizing impulse.
  • a ktelevision system wherein a series of picture signals and synchronizing impulsesare used to produce a television image
  • a picture producing cathode ray tube meansior generating a beam of electrons in said tube, means for modulating the intensity of the beam of electrons, means for deflecting the beam of elec- Vtrons in substantially mutually perpendicular fdirectons, relaxation oscillator deflection voltage generating means for energizing the beam deflecting means, a discharge tube including a cathode, a control electrode and an anode, means connected to said anode responsive to ⁇ syn chronizing impulses for controlling the deflection voltage generating means, means for applying the series of picture signals and synchronizing impulses to the cathode o said tube, means for biasing the control electrode to a predetermined negative potential -relative to the cathode normally to prevent thev ow of electronic current 'through the tube and means for coupling the control electrode to the deflection voltage
  • an image producing cathode ray tube having a target element, means in said tube for generating a beam of electrons and for directing the beam upon the target, means for modulating the intensity of the beam of electrons to control the intensity of the electro-optical images developed on the target, means for deecting the beamof electrons in substantially mutually perpendicular directions, deectionenergy generating means for energizing the beam deecting means, a discharge tube including a cathode, a control'electrode and an output electrode for separating the synchronizing and picture signais, means connected to said output electrode and responsive to the separated synchronizing impulses Afor controlling the deiiection energy generating means, means for applying the series .means for coupling the control electrode to the,r
  • a television receiver including means for amplifying' a radio frequency carrier amplitude tion cycles, a discharge tube including a cathode, a pair of control electrodes and an output electrode, means for impressing the picture signals and the synchronizing impulses between the cathode and control electrode of said discharge tube and also upon the electron beam modulating electrode, synchronizing impulse differentiating means connected to the output electrode of said tube for controlling the operation of the beam deflection generators to maintain the prel determined cycles under the control of received signals, means for biasing said control electrode .relative to the cathode to a predetermined negative potential sufficient normally to prevent con- ⁇ duction within the tube, and capacitive means for separately coupling the control electrodes to each of the beam deflection energy generators so as ultimately to reduce the bias to predetermined threshold value at a time immediately preceding the arrival of synchronizing impulses whereby the tube becomes substantially instantaneously conducting at time periods when synchroni'zing impulses are impressed thereon.
  • a television receiver including means for amplifying a radio frequency carrier amplitude modulated by a series of ⁇ picture signals and synchronizing impulses, detector means for producing demodulated picture signals and synchronizing impulses, a picture reproducing cathode ray tube including means for producing a ⁇ beam of electrons, means for modulating the .beam of electrons, means for deilecting the beam in a vertical direction and means for deecting the beam in a horizontal direction, vertical and horizontal beam deection generators connected respective- 1y to the vertical and horizontal beam deflecting means, a discharge tube including a cathode, a pair of control electrodes and an anode, means for impressing thel picture signals and the synchronizing impulses upon the cathode of said tube and upon the electron beam modulating electrode, synchronizing signal impulse differentiating means connected to the'anode of said tube for controlling the operation of the beam deflection generators, means for biasing said control electrodes to a predetermined negative potential relative to the cath
  • a television receiver including means for amplifying a radio frequency carrier amplitude modulated by a series of picture signals and synchronizing impulses, detector means for producing demodulated picture signals and synchronizing impulses, a picture reproducing cathode ray tube ⁇ including means for producing a beam of electrons, means for deflecting the beam in a vertical direction and means for deilecting the beam in a horizontal direction, vertical and horizontal beam deiiection'generators connected respectively to the vertical and horizontal beam deflecting means, a discharge tube including a cathode, a pair of control electrodes and an anode, means for impressing the synchronizing impulses between the cathode and control electrode of said tube, synchronizing impulse respon ⁇ sive means connected to the anode of said tube for controlling the operation of the beam deflection generators, means for biasing said control electrodes to a predetermined potential relative to the cathode normally to prevent conduction within the tube, and means for coupling the control electrodes to the beam deflection

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)
  • Television Systems (AREA)
US57870A 1935-01-09 1936-01-07 Television transmission method Expired - Lifetime US2227002A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE468505X 1935-01-09

Publications (1)

Publication Number Publication Date
US2227002A true US2227002A (en) 1940-12-31

Family

ID=6540859

Family Applications (1)

Application Number Title Priority Date Filing Date
US57870A Expired - Lifetime US2227002A (en) 1935-01-09 1936-01-07 Television transmission method

Country Status (7)

Country Link
US (1) US2227002A (xx)
AT (1) AT148929B (xx)
BE (1) BE413031A (xx)
DK (1) DK58968C (xx)
FR (1) FR800353A (xx)
GB (1) GB468505A (xx)
NL (1) NL48126C (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483442A (en) * 1947-07-21 1949-10-04 Faximile Inc Page separation signal and pulse generator
US2587074A (en) * 1948-09-29 1952-02-26 Rca Corp Color television image reproducing system
US2605350A (en) * 1948-10-23 1952-07-29 Rca Corp Synchronizing signal separator circuit
US2621245A (en) * 1947-09-09 1952-12-09 Rca Corp Color scanning system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2580672A (en) * 1947-11-14 1952-01-01 Bell Telephone Labor Inc Saw-tooth generator and system utilizing it

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483442A (en) * 1947-07-21 1949-10-04 Faximile Inc Page separation signal and pulse generator
US2621245A (en) * 1947-09-09 1952-12-09 Rca Corp Color scanning system
US2587074A (en) * 1948-09-29 1952-02-26 Rca Corp Color television image reproducing system
US2605350A (en) * 1948-10-23 1952-07-29 Rca Corp Synchronizing signal separator circuit

Also Published As

Publication number Publication date
FR800353A (fr) 1936-07-03
GB468505A (en) 1937-07-06
NL48126C (xx)
BE413031A (xx)
AT148929B (de) 1937-03-10
DK58968C (da) 1941-08-25

Similar Documents

Publication Publication Date Title
US2681379A (en) Signal operated automatic color control circuits
US2227002A (en) Television transmission method
US2300942A (en) Television carrier-signal receiver control system
US2607847A (en) Vertical retrace blanking
US2298863A (en) Image transmission system
US2881245A (en) Phase shifting circuits for color television receiver
US2502213A (en) Intelligence transmission system
US2435736A (en) Frequency modulated picture receiver
US2240593A (en) Television synchronizing and control system
US2240533A (en) Automatic control of television receiving systems
US2543037A (en) Television receiver
US2543066A (en) Automatic picture phasing circuit
US2256529A (en) Synchronizing signal separator circuit
US2236066A (en) Television apparatus
US2300452A (en) Combined power supply and scanning generator system
US2574229A (en) Flywheel synchronization system
US2203634A (en) Television system
US2568541A (en) Television signal mixing circuit
US2589927A (en) Keyed automatic gain control and sync separator
US2299292A (en) Automatic volume control system
US2198969A (en) Television scanning system
US2298864A (en) Synchronizing system
US2269524A (en) Synchronizing-signal separating apparatus
US2118352A (en) Periodic voltage generator
US2096877A (en) Television and like system