US2006803A - Short wave receiver - Google Patents

Short wave receiver Download PDF

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Publication number
US2006803A
US2006803A US543865A US54386531A US2006803A US 2006803 A US2006803 A US 2006803A US 543865 A US543865 A US 543865A US 54386531 A US54386531 A US 54386531A US 2006803 A US2006803 A US 2006803A
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United States
Prior art keywords
tube
circuit
screen
detector
short wave
Prior art date
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Expired - Lifetime
Application number
US543865A
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English (en)
Inventor
Grimes David
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RCA Corp
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RCA Corp
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Filing date
Publication date
Priority to BE389157D priority Critical patent/BE389157A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US543865A priority patent/US2006803A/en
Application granted granted Critical
Publication of US2006803A publication Critical patent/US2006803A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/163—Special arrangements for the reduction of the damping of resonant circuits of receivers

Definitions

  • 1t is one of the main objects of my present invention to provide in'a short wave radio receiver,A a novel and highly improved method of securing regeneration in the detectorv stage oompris'ing an electron discharge tube of the screen IU grid type.
  • Another important object of the present invention is to provide in a short Wave radio receiver employing a screen grid detector a novel and highly efficient arrangement for controlling f5 regeneration, the arrangement comprising a variable impedance for regulatingthe potential ap. plied to the screen of the detector tube.
  • Another object of the presentinvention is to provide in a short Wave radio receiver avstage of tuned radio frequency amplication employ ing a screen grid tube, and a succeeding .detector stage havin-Cf a tunable input circuit, a common means for transferring energy from the output Circuit of the amplifier tube to the said tunable input circuit of the detector stage and siml taneously transferring energy from the output circuit of the detector stage to its tunable input circuit, Y t
  • Still another object of the present invention is to provide a short wave receiver adapted for use in connection with signals having Wavelengths below one hundred meters, said receiver being arranged for energization of its circuits from an alternating current source employing a-rectifer,
  • Still another object of the present invern ⁇ tion is to provide for use with a Shortwave receiver employing a screen grid detector utilizing regeneration control means in the screen circuit, an arrangement for energizing the circuits of said receiver from an alternating current powel ⁇ line source, said arrangement including a double Wave rectier circuit anda Succeeding lter oil"-A cuit, there being buier capacities utilized inthe anode .circuits of the rectier to, suppress ultrahighharmonicsof the fundamental frequency of said source.
  • VStill-other objects of the present invention are of short wave radio receivers, andto particularl ,provide a short wave radio receiver, adapted-for additional means being associated with saidrec ⁇ operation with wavelengths substantially below a hundred meters whichis not only reliable in operation', but economically manufactured and assembled.Y .a y
  • FIG. 1 in purely diagrammaticv fashf ion, an ,arrangement forreceiving short waves Within a wave length range .ofthe order of 15 to v meters inclusive.
  • the collecting means in Fig. l, comprises any well known type of signal energy collecting such as agrounded antenna circuit A, G.
  • the collecting means is coupled, as at Y M, to the input circuit of a stage of tunedradio frequency amplificatonwhich includes a screen grid tube I.A
  • the input electrodes of .the tube are connected to a re'Sonant circuit including a va riable condenser .2 adapted to tune the radio frequency amplification stage to the desired short wave frequency.
  • y l a re'Sonant circuit including a va riable condenser .2 adapted to tune the radio frequency amplification stage to the desired short wave frequency.
  • the cathode of the tube I includes the usual gridfbasing resistor 3 having a value of about 450 ohms.
  • the resistor is shunted by a radio frequency by-pass condenser 4 having a value of about 0.6 microffarads.
  • the screen circuit of the tube includes a resistor 5, having a value of about 145.0 ohms, a radio frequency by-pass ca.- pacitysyof'aboutlthesamemagmtude as the ca.
  • pacity I being connected between the positive leg of thecathode and .the screen element.
  • a f tblifzlillll 'lf providespositive Y potentiarfor the screen velement of tube I, the conductor 'l being .connected to an appropriate tap 8 on any well knowntype of, voltage divider resistor 9 disposed in the power supply circuit. It Will be noted that the .conductor 1 vis connectedrtoA a point on the resistor 9 such that a potential of 90 volts is appliedto the screen element ⁇ of i tube I. kThe anodeV of the .screen grid tgube lI has potential applied, to a path which includes;
  • variable condenser I8 is utilizedfor uning the resonant input circuit of the detector age tothe same frequency toA which the inputcircuitvof the#y amplifier tube I has been tuned.f
  • the usual seriescapacity I9 and grid leak resistor 20 areprovided in the grid circuit of tube I1 to provid@ @etere-, tion.
  • the screen element ofthe tube I1 is Vco'n-v nected through conductors 2
  • Vthe detector tube canbe applied to the screen element of detector tube .si Y l L 1
  • the ⁇ anode of Vthe detector tube has potential applied to it through a path which includes a coil 29, "a resistor. 30 having afvalue- ⁇ of about 0.1 megohms, .conductor 3
  • The'audio frequency amplifiercarrltye ⁇ of any type well known to those skilled in the'iart, and for example, Vmayinclude one, or more, stages y o f audio frequency amplification embodying; single tubes, ⁇ and a final power amplifier embodying a push pull stage.
  • the amplifier does not compriseV the present invention, 4'it need not be described in any furtherl detaihjexcept to point out that the output of the audiovfrequen'cy amplifier may be utilized in any wellknown inanner, asjby a loud speaker, or head L Jhones,V orany ,other desired audible, ⁇ and 'even visual, repro,- Vducen .l 'The coil II has a dual ⁇ )function accordirs'ii the present invention. fIt serves-fto'tranlsffer ain# plied signalV energy from .'Vtheanode circuit 'of the jscreen ⁇ grid'y tube VI t ⁇ o 'the resonant input;
  • coils are preferably linter-v Y wound ,to piuvidthis optimum ppnuinun.:
  • the detector stage is regenerative, the regeneration being secured through la path which includes the con H. "It wi11, therefore-be seen that the latter functions as the primary coil of interstage transformer and simultaneously as a feed-back coil in a regenerative detector stage.
  • regeneration in the detector stage is regulated in a novel manner, the regulation ,being securedV by means Y kof a variable impedance in the screen circuit of'v rthe detector tube I1.
  • A'the present invention utilizes the action of the zscreen element to control regeneration. That isto say, the potential applied to the'screen elementof tube' I1 is controlled by means of the variable -resistor comprising the variable contact and the resistor 26. Y A,
  • variable impedance inthe' screen, circuit controls regeneration of thedetect'or stage
  • the regeneration is contolled by Vchanging theV gain Von the'tube IIT by varying the'screenvoltage as described above, through a path including condenser 3,2, lead ZI,
  • -V Condenser 32 has been addedy toaugment the self-capacity, ofthe tube existingbetweenplate and screen. "This increases thelregenerative action enormous. Choke- 29 confines the radio frequency energy to its proper, Y path;l l Y vTIrifadapting the present short wave receiver for usein connection with an alternating current Since the arrangement is vWell known to those Y skilled in the art, only the connection between thevanodels of therectifler and thepowersupply circuit are shown.
  • Vpower line s'ource a double wave rectifier-35 is 'secondary ⁇ 36, is'lconnected through a conductor
  • the filter ca-V Dacity adjacent tothe rectii'ler'm'a'y havev a value of 2 micro-farads, while the succeeding ca.-
  • paclties 4I' mayV each have a ,value'of 3 microfarads, while eachpof the capacities 42 following the last capacity 4I', may have a value of about 1 micro-farad.
  • each choke 42 mayy have a value of about 1000 ohms and henries at 100 mils drain.
  • Anode potentials for the audio frequency amplifier tubes may be taken oif from point 43, and the high potential terminal of the voltage dividei ⁇ 9. Illustrative values of such potentials are given as 250 volts, it being understood that potential is utilized usually-for the power amplier tube, and 180 volts to be utilized on t'ne earlier audio frequency amplifier tubes. However, it is believed that these arrangements are so Well known that they need not be described in any further detail.
  • Fig. 2 there is graphically shown the operation of the double wave rectifier.
  • the rectifier 35 functions to convert the alternating wave form into a pulsating uni-directional wave form.
  • alternate half cycles are shown in full lines, while half cycles between the full line half cycles are shown in dotted lines.
  • each of these buffer condensers is preferably 0.01 micro-farads.
  • buffer condensers When buffer condensers are employed, as shown in Fig. 1, in con- Y nection with the anodes of the rectifier tube, there is secured a gradual slope in the cut-off between alternate half cycles. This is shown in Fig. 2 by the reference numeral 5I. It will, therefore, be seen that by employing buffer condensers from the anodes of the double wave rectifier to ground,.hum frequencies about 3,000,000 cycles are effectively eliminated, and that this is secured by changing the sharp cut-olf action of the rectifier to a gradual slope.
  • a regenerative circuit comprising a space discharge device provided with anode, cathode and grid electrodes having external connections for forming input and output circuits for said device, a screen element in said device, a source of positive potential connectedto said screen element, a path between the output and input circuits for feeding energy from the output to the input in regenerative phase, and means comprising a, screen potential varying means associated with said screen element for determining the extent of the regenerative feed-back through said path.
  • a circuit including an electron discharge tube of the screen grid type having input and output circuits, a current source for energizing said tube and a tapered impedance shunted across said source at least a portion of which is included in said output circuit, a feedback circuit for transferring energy from said output circuit to said input circuit, a resistance shunted across at leastr a portion of said impedance, a circuitV including at least one reactive element connected between the screen element and cathode of said tube and means for variably connecting a point of said last named circuit to said shunt-ing resistance for varying Within predetermined limits the potential impressed upon the screen element relative to the cathode of said. tube and thereby control the transfer of energy through said feedback circuit.
  • step in the method of controlling the degree of regeneration which comprises varying the potential applied to the screen element of Athe tube and thereby changing the amplifying characteristics of the tube whereby the flow of energy from the output to the input thereof is controlled.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
US543865A 1931-06-12 1931-06-12 Short wave receiver Expired - Lifetime US2006803A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE389157D BE389157A (is") 1931-06-12
US543865A US2006803A (en) 1931-06-12 1931-06-12 Short wave receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US543865A US2006803A (en) 1931-06-12 1931-06-12 Short wave receiver

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US2006803A true US2006803A (en) 1935-07-02

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2657306A (en) * 1943-03-13 1953-10-27 Williams Frederic Calland Radio receiving circuit arrangement

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2657306A (en) * 1943-03-13 1953-10-27 Williams Frederic Calland Radio receiving circuit arrangement

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Publication number Publication date
BE389157A (is")

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