US2266731A - Television receiver circuit - Google Patents

Television receiver circuit Download PDF

Info

Publication number
US2266731A
US2266731A US267231A US26723139A US2266731A US 2266731 A US2266731 A US 2266731A US 267231 A US267231 A US 267231A US 26723139 A US26723139 A US 26723139A US 2266731 A US2266731 A US 2266731A
Authority
US
United States
Prior art keywords
tube
potential
resistance
impulses
television receiver
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
US267231A
Other languages
English (en)
Inventor
Andrieu Robert
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.)
Telefunken AG
Original Assignee
Telefunken AG
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 Telefunken AG filed Critical Telefunken AG
Application granted granted Critical
Publication of US2266731A publication Critical patent/US2266731A/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
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/52—Automatic gain control
    • H04N5/53—Keyed automatic gain control

Definitions

  • auxiliary signal sent out in conjunction with the synchronizing impulses used in sequential and interlaced scanning.
  • the said auxiliary signal is separated by the aid of so-called keying impulses from the rest of the transmitted signals and thus a regulator or control potential is obtained which corresponds to the prevailing amplitude of the auxiliary signal in accordance with the amount of fading existing at the time.
  • the keying impulses in the scheme known in the prior art have been obtained by a time-base generator. comprising two mutually controlling tubes (multivibrator) which is controlled by the synchronizing impulses, or else they were produced by artificial delay introduced in the synchronizing impulses themselves.
  • the keying impulses are secured from the means serving for line or frame deflection so that it is possible to dispense with the ratchet wave or time-base generator and the delay means hereinbefore mentioned.
  • I is a condenser which is charged from a source of D. C. potential across resistance II in direct proportion to the time.
  • the tube I3 which is connected in a blocking oscillator scheme, and which in some suitable circuit organization may be subjected to control action produced by synchronizing impulses, discharges the condenser In each time a synchronizing impulse comes in.
  • a drop of potential is brought about across the resistance I4 in the cathode lead of tube I3, the said potential drop having a sense as indicated by the plus and minus signs. This drop of potential serves the object to open the tube I5 whose cathode is connected with a suitable positive potential relative to ground.
  • the condenser resistance I4 By connecting the condenser resistance I4, conditions could also. be made so that the drop of potential across resistance I4, after termination of the plate-current impulse, initially decays slowly with the result that tube I5 is kept open for a period of time that is greater than the plate-current impulse length.
  • Grid 3 of tube I5 is fed with the entire signal spectrum which has been transmitted from a distant point, that is to say, either in the form of a radio frequency or of an intermediate frequency potential or else after rectification of the carrier frequency.
  • tube I5 by the action of the keying impulse furnished from resistance I4 is open only during the synchronizing impulse and during a limited length of time adjoining the said impulse, it is possible to tap across resistance I6 a voltage which will correspond to the transmitted auxil-' iary signal so that therefrom the fading-compensator or signal-volume control potential may be made.
  • Figure 2 shows an exemplified embodiment which also comprises a condenser I0, a resistance I I, and a blocking oscillator tube I3.
  • a condenser I0 In coupling relation with the transformer winding II included in the plate circuit of the said blocking oscillator tube is an auxiliary winding I8 which works upon a resistance I9 to which, optionally, a condenser 20 may be connected in parallel.
  • the cathode ,of tube I5 in this instance shall be assumed to be grounded as shown, and the lower end of winding I8 must then be united with a suitable negative biasing voltage.
  • Grid I of tube l5 again is fed with the signal spectrum consisting of the brilliance or video signals, the synchronizing impulses, and the auxiliary signal, in the form of radio frequency or video frequency energy so that a potential may be taken off across the resistance l6 whichcorresponds to the size of the auxiliary signal stabilized at the send end and arising at the receiving end.
  • an auxiliary coil 23 is in magnetic coupling relationship with the deflector coils 2
  • the lower end of the said resistanc 24 must be connected with a fixed biasing potential of such a size that grid I of tube I5 is impressed with the requisite negative biasing potential.
  • grid 3 of tube I5 as described by reference to Figure 1, is fed with the entire signal spectrum transmitted from the distant 6 in parallel relation to the point either in radio frequency or video frequency form so that the potential across the plate resistance l6 may be used as in Figures 1 and 2.
  • the keying impulses are obtained from the means which serve for line or frame defiection, that is to say, the sawtooth generator, for example, as described by reference to Figures 1 and 2 or else from the very deflector coil as described in connection with Figure 3.
  • the said keying impulses could be derived also from a circuit in series with the sawtooth generator for the picture co-ordinate that is con cerned.
  • a system for producing automatic volume control potentials in a television receiver comprising a first discharge tube having a cathode,
  • a pair of control electrodes and an anode means for applying a potential to one of the control electrodes to normally bias the tube to cut-off
  • a second discharge tube havinga cathode, a control electrode and an anode
  • means for applying synchronizing signal impulses to the control elec trode of said second discharge tube means for applying synchronizing signal impulses to the control elec trode of said second discharge tube, a resistance connected from the cathode of the second dischargetubeto a point of fixed potential, a condenser connectedi-n parallel with said resistance, means for.
  • a system for producing automatic Volume control potentials in a television receiver comprising a first discharge tube having a cathode, a pair of control electrodes and an anode, means for applying a potential to one of the control electrodes to normally bias the tube to cut-off, a second discharge tube having a cathode, control electrode and anode, means for applying synchronizing signal impulses to the control electrode of said second discharge tube with the polarity of the synchronizing impulses extending in a positive direction, a resistance connected from th cathode of the second discharge tube to a point of fixed potential, a condenser connected in parallel with said resistance, means for connecting the, cathode of said second discharge tube to the said one control electrode of the said first discharge tube to render said first tube conductive for shortintervals-of time coinciding .with the application of the synchronizing signal impulses to said second discharge :tube, means connected to the other control electrode for varying the conductivity of said first discharge tube during said.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
US267231A 1938-03-24 1939-04-11 Television receiver circuit Expired - Lifetime US2266731A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2266731X 1938-03-24

Publications (1)

Publication Number Publication Date
US2266731A true US2266731A (en) 1941-12-23

Family

ID=7993032

Family Applications (1)

Application Number Title Priority Date Filing Date
US267231A Expired - Lifetime US2266731A (en) 1938-03-24 1939-04-11 Television receiver circuit

Country Status (2)

Country Link
US (1) US2266731A (enrdf_load_stackoverflow)
BE (1) BE433409A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538519A (en) * 1949-06-23 1951-01-16 Avco Mfg Corp Keyed automatic gain control circuit with double time constant input voltage filter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2538519A (en) * 1949-06-23 1951-01-16 Avco Mfg Corp Keyed automatic gain control circuit with double time constant input voltage filter

Also Published As

Publication number Publication date
BE433409A (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
US2255484A (en) Automatic background control for television systems
US2284219A (en) Signal wave form indicating system
US2088495A (en) Electric discharge apparatus
US2285043A (en) Television receiver
US2097334A (en) Control circuits for cathode ray devices
US2402091A (en) Television system
US2628326A (en) Television apparatus
US2180364A (en) Cathode ray sweep circuits
GB395499A (en) Improvements in or relating to television systems and to electrical wave systems
US2607847A (en) Vertical retrace blanking
US2085402A (en) Method of and apparatus for producing electrical waves
US2105902A (en) Periodic voltage generator
US2229964A (en) Television synchronizing system
US2085409A (en) Television system
US2211860A (en) Electrical wave segregation circuit
US2266731A (en) Television receiver circuit
US2307218A (en) Thermionic valve circuit
US1999378A (en) Television system
US2178736A (en) Television apparatus
US2254344A (en) Sawtooth wave generator
US2871405A (en) Raster centering control
US2144351A (en) Deflecting circuit
US2343290A (en) Means for signaling with electronic commutators
US3144579A (en) Two gun storage tube utilizing pulse circuitry
US2708689A (en) Automatic frequency control of television deflection apparatus