US2240295A - Television receiver - Google Patents

Television receiver Download PDF

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Publication number
US2240295A
US2240295A US166287A US16628737A US2240295A US 2240295 A US2240295 A US 2240295A US 166287 A US166287 A US 166287A US 16628737 A US16628737 A US 16628737A US 2240295 A US2240295 A US 2240295A
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United States
Prior art keywords
circuit
coil
sound
frequency
intermediate frequency
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
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US166287A
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English (en)
Inventor
Gustave L Grundmann
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.)
RCA Corp
Original Assignee
RCA 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 RCA Corp filed Critical RCA Corp
Priority to US166287A priority Critical patent/US2240295A/en
Priority to FR843471D priority patent/FR843471A/fr
Priority to CH208107D priority patent/CH208107A/de
Priority to GB28169/38A priority patent/GB519727A/en
Application granted granted Critical
Publication of US2240295A publication Critical patent/US2240295A/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
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/60—Receiver circuitry for the reception of television signals according to analogue transmission standards for the sound signals

Definitions

  • My invention relates to television receivers and particularly to receivers designed for the reception of both pictures and sound.
  • Patent No, 2,165,794 issued Juiy l1, i939, in the name of Ralph 'S'. Holmes and assigned to the Radio Corporation of America, there is described and claimed a television receiver which is designed to be used in combination with a short Wave broadcast receiver.
  • a television receiver which is designed to be used in combination with a short Wave broadcast receiver.
  • a further object of my invention is to provide an improved circuit for taking the sound signal from a television receiver.
  • I employ between the first detector and the first I. F. amplifier of the television receiver a band pass coupling filter or transformer unit of the type described and claimed in Patent No. 2,199,604, issued May 7, 1940, to Horace C. Allen and Gustave L. Grundmann, and assigned to the Radio Corporation of America.
  • this tran..- former unit the tuned primary circuit and the tuned secondary circuit are coupled by means of an inductance coil or other impedance unit such as a condenser common to the two circuits.
  • the roadcast receiver is connected through a trap circuit to the high potential end of the above-mentioned inductance coil which will be .referred to hereinafter as the coupling coil.
  • the coupling coil and the circuit leading to the broadcast receiver are tuned to resonate et the I. F. sound carrier whereby sound signals are transferred efficiently to theV broadcast receiver.
  • the trap circuit is tuned to the frequency of the oscillator in the broadcast receiver whereby voltage from this oscillator is not fed into the picture I. F. channel.
  • FIG. 1 there is shown the first detector tube' l0 and the first I. F. tube I l of my improved television receiver.
  • the picture and sound signals on two separately modulated -carrier waves are supplied to ⁇ the first detector: l0 through a tunable selecting circuit l2 having a pass range wide enough to pass both modulated carrier waves.
  • the two carriers are spaced 3.25 megacycles apart.
  • the tunable selecting circuit l2 may comprise two tunable circuits I3 and
  • the 'coil I6 may be coupled through va transmissionline to a dipole antenna (not shown).
  • the first detector i8 may be of any suitable type such as a pentode 'having the screen grid and suppressor grid connected together for increasing the mutual conductance of the tube.
  • a suitable operating voltage is supplied to these grids through a filter resistor Il provided with a filter condenser 1'3.
  • the detector tube is selfbiased by means of a self-biasing resistor I9 in the cathode circuit, the resistor I9 being shunted by the usual bypass condenser 2l.
  • a tunable oscillator 22 is coupled in any suitable manner to the rst detector it; I'he vtuning condensers of the oscillator 22 and of the circuits I3 and l are ganged, as indicated by the broken lines, to permit tuning by the single knob 23.
  • the band pass coupling circuit between detector ill and amplifier Il comprises a tunable primary coil 2G, a tunable secondary coil 21 kand a common coupling coil 28.
  • a blocking condenser 25 is connected between coils 26 and 2l'.
  • Plate voltage is supplied to the plate of detector tube I through a filter resistor 29, the coupling coil 28 and the primary coil 26.
  • is connected between the high potential end of resistor 29 and ground.
  • Biasing voltage is supplied to the control grid of I. F. amplifier tube through a filter resistor 32 and a grid resistor 33.
  • a filter condenser 34 is connected between the high potential end of resistor 32 and ground.
  • the above-described coupling circuit includes a tuned primary circuit coupled to a tuned secondary circuit.
  • the tuned primary circuit may be traced from ground through the relatively large capacity filter condenser 3
  • Capacity 36 is the tuning capacity, the nal tuning adjustment being made by means of the coil 26 which has an adjustable magnetic core.
  • the 'I'he secondary circuit may be traced from ground through the filter condenser 3
  • the tuning capacity is the capacity 37, the nal adjustment being made by means of the coil 27 which has an adjustable magnetic core.
  • the primary and secondary circuits are so coupled and tuned as to pass the band of picture frequencies and to re.. ject signals at other frequencies, especially to reject the sound signals.
  • the picture signals only appear in the output circuit of the I. F. amplier and are supplied to other similar I. F. stages connected in cascade.
  • the screen grid and the suppressor grid of the amplifier tube assuming it is of the pentode type, are preferably connected together through a resistor 38 wherebythe mutual conductance of the tube is increased without causing oscillations. It has been found that in an I. F. stage there are undesired oscillations ifY the resistor 38 is omitted.
  • the circuit which supplies the sound signals to the broadcast receiver 24 comprises a conductor 4
  • the ground terminal of receiver 24 is grounded as indicated.
  • the conductor 46 is provided with a grounded shield' 41.
  • a twisted shielded pair of conductors may be employed.
  • the broadcast receiver chassis should be connected directly to, that is, grounded to, the chassis of the television receiver, whereby there is no potential difference between the two chassis. Otherwise, the conductor transferring sound signal from the television receiver to the broadcast receiver, acting as an antenna, will pick up interfering signals, such as automobile ignition noise, and cause noise in the broadcast receiver output.v
  • the sound signal circuit is tuned to the frequency of the sound signals, 9.75 megacycles in the specic case illustrated, by adjusting the condenser 44.
  • the rejection circuit 42--43 is tuned to the frequency of the broadcast oscillator,
  • this coil being provided with an adjustable magnetic core.
  • circuit which is series resonant to sound signals may be traced from ground, through filter condenser 3
  • Fig. 3 'Ihe response characteristic at the broadcast receiver end of the conductor 46 is shown in Fig. 3. It will be seen that the response at the 9.75 megacycle sound signal is very good, while the response at the broadcast oscillator frequency of 10.21 megacycles is very poor.
  • the broadcast receiver may be connected to a separate broadcast antenna for the reception of regular broadcast sound programs, it is preferred to provide means whereby the television antenna and transmission line may be utilized as the broadcast antenna.
  • the midpoint of the input coil I6 is connected to a switch arm 5
  • the conductor 53 connects the contact point 54 to the conductor 46 whereby, when the switch arm 5
  • a switch 56 is provided between conductor 46 and condenser 44, this switch being thrown to the dotted line position when switch arm 5
  • switch I asindicatedby the broken line 51.
  • ; and 55 should be ganged with the television receiver power switch 58 as indicated by the broken line 59.
  • switch 55 isturned oiff the switches 5
  • a band pass coupling network connected between said detector and said amplifier and having a pass range for passing the picture modulated intermediate frequency carrier wave substantially to the exclusion of the sound modulated intermediate frequency carrier wave, said network comprising a tuned primary circuit having a primary coil and a coupling impedance unit, and a tuned secondary circuit having a secondary coil and including said coupling impedance unit, and a circuit connected to the alternating current high potential end of said coupling impedance unit for supplying the sound modulated intermediate frequency carrier wave to a frequency converting unit having an oscillator therein, said circuit including a parallel resonant circuit tuned to the frequency of said oscillator, and means for making said circuit and said coupling impedance unit series resonant at the frequency of said sound modulated intermediate frequency carrier wave.
  • a television receiver comprising a first detector and an oscillator coupled thereto for converting an incoming picture modulated carrier wave and an incoming sound modulated carrier wave to an intermediate frequency picture signal and to an intermediate frequency sound signal, said modulated carrier Waves having a certain frequency spacing, an intermediate frequency amplifier tube, a band pass coupling network connected between said detector and said amplier tube and having a pass range for passing the intermediate frequency picture signal to the exclusion of the sound signal, said coupling network comprising a tuned primary circuit including a coupling impedance unit and a tuned secondary circuit including said coupling impedance unit, and a circuit connected to the alternating current high potential end of said coupling impedance unit for supplying the sound signals to a frequency converting unit having an oscillator therein, said circuit including a parallel resonant circuit tuned to the frequency of the oscillator in said converting unit and a reactance unit in series with said parallel resonant circuit and having such reactance that said circuit and said coupling impedance unit are series resonant at the carrier
  • a bandi pass coupling network connected-between said detector and-said amplifier and having a pass range for passingfthe picture modulated intermediate frequency oarrier wave substantially to the exclusion ofthe sound modulated intermediate frequency carrier wave, said network comprising a tuned primary circuit having a primary coil anda coupling coil and av tuned secondary circuit having a secondary coil and including said coupling coil, and a circuit connected to the alternating current high potential end of said coupling coil for supplying the-sound modulated-intermediate frequency carrier wave to a frequency converting unit having an oscillator therein, said circuit including aparallel resonant circuit tunedv to the frequency of said oscillator and means for making said circuit and said coupling coil series resonant at the frequency of said sound modulated intermediate frequency carrier wave.
  • a television receiver comprising a iirst detector and an oscillator coupled thereto for converting an incoming picture modulated carrier wave and an incoming sound modulated carrier wave to an intermediate frequency picture signal and to an intermediate frequency sound signal, said modulated carrier waves having a certain frequency spacing, an intermediate frequency amplifier tube, a band pass coupling network connected between said detector and said amplifier tube and having a pass range for passing the intermediate frequency picture signal to the exclusion of the sound signal, said coupling network comprising a tuned primary circuit having a primary coil and a coupling coil and a tuned secondary circuit having a secondary coil and including said coupling coil, and a circuit connected to the alternating current high potential end of said coupling coil for supplying the sound signals to a frequency converting unit having an oscillator therein, said circuit including a parallel resonant circuit tuned to the frequency of the oscillator in said converting unit and a condenser in series with said parallel resonant circuit and having such capacity that said circuit and said coupling coil are series resonant at the
  • a television receiver and a frequency converting unit said converting unit including an oscillator
  • said receiver comprising a tunable selecting circuit for selecting a picture modulated carrier wave and its accompanying sound modulated carrier wave
  • means including a first detector for converting the output of said selecting circuit to an intermediate frequency picture signal and to an intermediate frequency sound signal, an intermediate frequency amplifier, a coupling network connected between said first detector and said amplier and having a pass range for passing the intermediate frequency picture signal substantially to the exclusion of the sound signal, said network comprising a tuned primary circuit having a primary coil and a coupling coil and a tuned secondary circuit having a secondary coil and including said coupling coil, and a sound signal circuit connected between the alternating current high potential end of said coupling coil and an input terminal of said frequency converting unit, said sound signal circuit including a parallel -resonant circuit tuned to the frequency of the oscillator in said converting unit and also including means for making said coupling coil and said sound signal circuit series resonant at the frequency of the intermediate frequency sound signal.
  • a television receiver and a frequency converting unit said converting unit including an oscillator
  • said receiver comprising a tunable selecting circuit for selecting a picture modulated carrier wave and its accompanying sound modulated carrier wave
  • means including a first detector for converting the output of said selecting circuit to an intermediate frequency picture signal and to an intermediate frequency sound signal,an intermediate frequency amplifier, a coupling network connected between said first detector and said ampliiier and having a pass range for passing the intermediate frequency signal substantially to the exclusion of the sound signal
  • said network comprising a tuned primary circuit having a primary coil and a coupling coil and a tuned secondary circuit having a secondary coil and including said coupling coil
  • a sound signal circuit including a conductor having a grounded shield connected between the alternating current high potential end of said coupling coil and an input terminal of said frequency converting unit, said sound signal circuit including a parallel resonant circuit tuned to the frequency of the oscillator in said converting unit and also including means for making the circuit including said coupling coil, said sound signal circuit and the capacity

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Television Receiver Circuits (AREA)
  • Superheterodyne Receivers (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
US166287A 1937-09-29 1937-09-29 Television receiver Expired - Lifetime US2240295A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US166287A US2240295A (en) 1937-09-29 1937-09-29 Television receiver
FR843471D FR843471A (fr) 1937-09-29 1938-09-14 Perfectionnements aux récepteurs de télévision
CH208107D CH208107A (de) 1937-09-29 1938-09-27 Fernseh- und Tonempfangseinrichtung mit Überlagerungsempfang für kombinierte Sendungen, bei welchen die Trägerwelle für das Bild und die Trägerwelle für den Ton nahe beieinander liegen.
GB28169/38A GB519727A (en) 1937-09-29 1938-09-28 Improvement in television receivers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US166287A US2240295A (en) 1937-09-29 1937-09-29 Television receiver

Publications (1)

Publication Number Publication Date
US2240295A true US2240295A (en) 1941-04-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
US166287A Expired - Lifetime US2240295A (en) 1937-09-29 1937-09-29 Television receiver

Country Status (4)

Country Link
US (1) US2240295A (fr)
CH (1) CH208107A (fr)
FR (1) FR843471A (fr)
GB (1) GB519727A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2581159A (en) * 1948-05-28 1952-01-01 Rca Corp Tunable band pass amplifier for television
US2619536A (en) * 1948-12-09 1952-11-25 Zenith Radio Corp Electrical signal network
US2624838A (en) * 1945-12-07 1953-01-06 Int Standard Electric Corp Radio receiver employing band pass coupling circuit arrangements
US2676215A (en) * 1950-07-12 1954-04-20 Hartford Nat Bank & Trust Co Wide-band amplifier

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE967209C (de) * 1951-10-13 1957-10-24 Interessengemeinschaft Fuer Ru Kombiniertes Empfangsgeraet fuer Rundfunk- und Fernsehsendungen

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2624838A (en) * 1945-12-07 1953-01-06 Int Standard Electric Corp Radio receiver employing band pass coupling circuit arrangements
US2581159A (en) * 1948-05-28 1952-01-01 Rca Corp Tunable band pass amplifier for television
US2619536A (en) * 1948-12-09 1952-11-25 Zenith Radio Corp Electrical signal network
US2676215A (en) * 1950-07-12 1954-04-20 Hartford Nat Bank & Trust Co Wide-band amplifier

Also Published As

Publication number Publication date
GB519727A (en) 1940-04-04
CH208107A (de) 1939-12-31
FR843471A (fr) 1939-07-04

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