US2199273A - Short wave television transmitter - Google Patents

Short wave television transmitter Download PDF

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Publication number
US2199273A
US2199273A US75403A US7540336A US2199273A US 2199273 A US2199273 A US 2199273A US 75403 A US75403 A US 75403A US 7540336 A US7540336 A US 7540336A US 2199273 A US2199273 A US 2199273A
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US
United States
Prior art keywords
grid
anode
short
wave
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 - Lifetime
Application number
US75403A
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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 US2199273A publication Critical patent/US2199273A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/38—Transmitter circuitry for the transmission of television signals according to analogue transmission standards
    • H04N5/40—Modulation circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/16—Amplitude modulation by means of discharge device having at least three electrodes
    • H03C1/18—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid
    • H03C1/24—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid modulating signal applied to different grid
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/38—Transmitter circuitry for the transmission of television signals according to analogue transmission standards

Definitions

  • the object of the following measures according to the invention is to solve in satisfactory manner the earthing problem. and the combined problem of high-frequency earthing and lowfrequency coupling with the modulator by the use of suitable series-resonance connectionaauxiliary chokes and tuning condensers.
  • Fig. 1 shows a practical example as applied to simultaneous modulation and earthing. This refers to a three-grid modulation connection making use of a -electrode valve I, which has already been explained in principle in the earlier specification Ser. No. 717,309. In this valve the cathode 2 is linked up with a counterpoise, for
  • the innermost grid 4 is connected through the medium of; a coil 5 with an exciting circuit .6.
  • This circuit oscillates with half the frequency 6 is preferably a quartz oscillator, for example on the 14-metre wave.
  • a detrimental coupling by way of the inner capacities of grid and anode and the assembly capacities is already reduced in the first order by the tuning of Ito the 'T-metre wave.
  • the two remaining grids of the ti-pole tube l viz., the screening grid 8 and the 'so-called' intercepting grid, or better, reflecting grid 9, belong to two other modulating circuits.
  • the screening grid 8 is connected with the image-current amplifier I 0; whilst the reflecting grid 9 is coupledwith an impulse apparatus H, which for the purpose of synchronisation produces sharp, negatively directed synchronisation impulses at the end'of each line and? image.
  • Thedifliculty in the operation of this connection resides in practice in the fact that even in the case of valves, in which galvanometricdimensions have resulted in faultlessoperation of'the grid control, a dynamicseparation of the anode oscillation cannot be successfully accomplished even with the strongest negative impulses of In or II; To the contrary, even in the case of complete electronic blocking of the modulating valve I, there always remains a considerable proportion of residual high-frequency potential in the .anode circuit 1, which is conveyed byway of the coupling condenser, l2 to the later output amplifying stages of the transmitter. This condition is also not affected by screening partitions l3 which may be introduced between the grid and anode circuits of the modulator l.
  • control circuit l9 to a special grid, which is provided between the reflecting grid 9 and the'anode I and in turn possesses the potential of the cathode.
  • the control of this grid then also occurs in wattless fashion.
  • the reflecting grid 8 is then no longer modulated, but serves merely for suctional action on the electronic current, which otherwise would flow to the screening grid 8 and then load the image amplifying circuit Ill/l8.
  • Fig. 2 there is shown such an embodiment of the invention, wherein 9'. is the additional fourth grid lying between. the reflecting grid 9 and the anode I.
  • the elements 23 and 24 represent the series connection of this additional grid for earthing the carrier oscillations.
  • the element 25 performs the D.-C. connection to the cathode and earth respectively.
  • amodulator comprising a multielectrode modulator valve having at least an earthed cathode, an anode, and three grids, an oscillation generator, a synchronizing impulse generator, and an image contents current generator, an oscillatory circuit in the anode circuit of said valve, each of said generators being connected to one ofsaid grids two series connections comprising each at least one condenser and one inductance so dimensioned as'to be in .series resonance with respect to the frequency of the oscillations of said oscillation generator, the
  • a modulator comprising a multieIectrode modulator valve having at least an earthed cathode, an anode, and four grids, an oscillation generator, a synchronising impulse generator, and an image contents current gens erator, an oscillatory circuit in the anode' clrcuit of said valve, each of said generators being connected to one of three of said four grids, two series connections comprising each at least one condenser and one inductance so dimensioned as tobe in series resonance with respect to the frequency of the oscillations of saidoscillation generator, three of said grids which are the next ones to said anode being-connected to earth by means of said series connectionsythe firstand the third of said grids numbered from the anode being connected to the synchronising impulse generator circuit and the image contentsimpulse generator circuit respectively, the second grid numbered from the anode being supplied with a suitable positive bias potential higher than that of said third grid numbered from
  • a short-wave or ultra-short-wave transmitter preferably for television purposs'a-modulator comprising a multi-electrode modulator tube having an anode, a cathode and several interposed electrodes, a plurality of energizing circuits for supplying said interposed electrodes with short or ultra-short oscillations and modulation currents having frequency values up to very high frequencies to be modulatedon'said short or ultra-short oscillations, said electrodes supplied with modulation currents being connected to earth as regards said short or ultra short 0scillations by means of an inductance and a capacity connected in series as to form a seriesresonant circuit resonating at said short or ultrashort oscillation, and being simultaneously connected to the modulation and bias sources respectively by means of chokes and resistances.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
US75403A 1935-04-30 1936-04-20 Short wave television transmitter Expired - Lifetime US2199273A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2199273X 1935-04-30

Publications (1)

Publication Number Publication Date
US2199273A true US2199273A (en) 1940-04-30

Family

ID=7989682

Family Applications (1)

Application Number Title Priority Date Filing Date
US75403A Expired - Lifetime US2199273A (en) 1935-04-30 1936-04-20 Short wave television transmitter

Country Status (3)

Country Link
US (1) US2199273A (me)
FR (1) FR805548A (me)
NL (1) NL50094C (me)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2837637A (en) * 1954-12-09 1958-06-03 Daystrom Inc Signal mixer circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2837637A (en) * 1954-12-09 1958-06-03 Daystrom Inc Signal mixer circuit

Also Published As

Publication number Publication date
NL50094C (me)
FR805548A (fr) 1936-11-21

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