US1872231A - Wireless receiving set - Google Patents

Wireless receiving set Download PDF

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Publication number
US1872231A
US1872231A US395824A US39582429A US1872231A US 1872231 A US1872231 A US 1872231A US 395824 A US395824 A US 395824A US 39582429 A US39582429 A US 39582429A US 1872231 A US1872231 A US 1872231A
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US
United States
Prior art keywords
resistance
grid
anode
tube
lead
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
US395824A
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English (en)
Inventor
Bol Cornelis
Posthumus Klaas
Unk Jacob Marinus
Morel Cornelis Hendrik
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RCA Corp
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RCA Corp
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Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
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Publication of US1872231A publication Critical patent/US1872231A/en
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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
    • H04B1/1607—Supply circuits
    • H04B1/1623—Supply circuits using tubes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0064—Earth or grounding circuit

Definitions

  • the invention relates to wireless receiving sets in which a detector is preceded by one or more high frequency amplificationstages and is followed by one-or more low frequency amplification stages and in which the apparatus for the supply of the anode voltages are incorporated in the and the grid biases set.
  • the invention concerns an improvement in the mutual arrangementand screening of the various parts, owing to which 1ndependently of the number of ampl ficatlon stages and of the degree of amplification. of. each and the grid biases are-combined with the low frequency amplifier. (which for itself may consist of one or more stages) so as to.
  • both the high frequency amplifier and the detector are mounted within a metal case which'is divided by metal partitions into compartments members constituted, for example by com-.
  • alternating current meanswhich mostly afiords: alternating current. In'that case theproduction of ahum ming noise isbest avoided. by having the. cathode of the'de'tector. and. preferably also the cathodes of. the high frequency; amplifiers indirectly heated: by the alternating current.
  • offthefirstvhigh frequency tube is. lower than that ofgthe second andso on. Thisis desirable in order to avoid distortion as otherwise it"might occur that the second high. frequency tube would be pinched off to such anextent that it would no longer be able to amplify the oscillationamplitudes suppliedby the-preceding high frequency. valve without causing distortion.
  • .1 denotesan. aerial which isconnected'through a small'aerialcondenser 2*-to'the firsttunable high frequency circuit.
  • This circuit consists of two coils 3 and 4 connected in series, of which the latter may be short-circuited by a switch 5, of a vari a ole condenser 6 and a large condenser 9.
  • the circuit is connected to the control grid 17 of the firsthigh frequency tube I and at the other end it is connected on one hand through a resistance 7 and a lead 8 to a slider adapted tobe moved along a resistance63to be further described and on the other hand, beyond a condenser 9, at 14 to a lead 10 which is earthed at 13, through a lead 11 and a large condenser 12.
  • the high frequency tube 1 comprises a cathode -15 which is connected to earth is supplied by an auxiliarywinding 81 of a transformer T.
  • the tube I contains a screening grid 18 and an anode 19.
  • the feeding of the screeninggrid is effected through a resistance 22, a lead/40, a resistance 39,, a resistance 79, and a'resistance- 77 from a high tension supply unit which. will hereinafter be' described more fully.
  • the anode 19 is'conne cted to the upperend of the second tunable high frequency circuit which similarly consists of coils 23. 24, a short-circuiting switch 25, a variablecondenser 26 and a fixed condenser '37.
  • circuit is connected through a grid condenser 27 to the control grid 28 of the second high frequency tube II, said grid being connected through a leakage resistance 29 and a resistance 38 to the lead 8.
  • the lower end of the resistance 29 is connected through alarge condenser 34 to the-earth lead 10."
  • the grid biases to be applied to the control grids of the tubes I and IIfcan consequently be controlled'by the displacement of the slider at the end of the lead 8 along the resistance 63 when the latter is traversed by current.
  • the tube II further comprises a cathode 30 with heating eleinent 31 which is fed by the above-mentioned auxiliary winding'81 of the transformer T.
  • the cathode 30' is directly connected to-the earth lead 10 to which the heating element 31 is connected through'a large condenser 35.
  • the t'ube'II further comprises a screening grid 32 and an anode 33.
  • the screening grid isfed through resistances 39, 7 9, 77 from the h gh tension supply unit, from which it is obvious that the potential of the grid 32 is constantly asmuch higher as that of the grid 18 as is the voltagedrop across the resistance 22, the purpose thereof being already above mentioned.
  • the anode 52 of the detector is connected through a choke coil 53 and the primary winding 67 of a low frequency transformer to the upper end of the resistance 79 which is connected through the resistance 77 to the plus pole of the high tension supply unit.
  • the two ends of the choke'coil 53 are connected through relatively small condensers (telephone-condensers) 54 and 55 to the earth lead 10 so that high frequency currents are thus kept outside the low frequency transformer.
  • One of theends of the secondary winding 68 of the low frequency transformer is connected to the control grid 69 of the final tube, which further comprises a screening grid 70 and an anode 71.
  • the other end of the winding 68 is connected through a resistance '66 to a stationary point 65 of a choke coil 64 of the high tension supply unit and is further connected through a large condenser 83 to the earth lead 1 0.
  • the screening grid 7 O is fed from the connecting points of the two resistances 77 .and 79.
  • the anode 71 of the final tube E leads through the primary winding 72 of an output transformer directly to the plus pole of the high tension'supply unit.
  • This output transformer is provided with two secondary windings 7'3 and 74 which may be differently dimensioned in order to be able to operate different loudspeakers and whose point of connection is earthed.
  • the grid 49 of the detector is connected through a switch 56 to plug bushes 57 between which a so-called gramophone adaptercan be connected, the other pole of this adapter'being connectedin this case through a resistance 58 to the connecting point of two resistances 62 and 63 of the high tension supply unit and through large condensers 59 to the earth lead 10.
  • the high tension supply unit which is also adapted'to supply the required grid potentials comprises a power transformer T whose primary winding can be fed directly from the lighting mains and which is provided with three secondary windings 81,82 and 83.
  • the winding 81 serves to feed the heating elements of the tubes I, II and D and the cathode of the final valve E.
  • a potentiometer 84 In parallel with the winding 81 is connected a potentiometer 84 the middle of which is earthed at 13 through a condenser 12.
  • the winding 82 is used for the'heating of the cathode of a rectifier G.
  • This rectifier has two anodes which are each connected to one ofthe ends of the secondary winding 83.
  • the middle of the winding 83 is connected through a large smoothing condenser 75 to the cathode of the rectifier and further through the choke coil 64 and through the resistances 63 and 64 connected in series therewith to the minus pole of the high tension supply unit.
  • this pole is'connected through a large condenser 76 to the plus pole which is connected in its turn to the cathode of the rectifier, the minus pole being connected to the earthed lead 10.
  • the highest positive potential occurs at the plus pole which is connected through the transformer winding 72 to the anode 71 of the final tube.
  • the anode 52 of the detector is connected through coils 53 and 67 to the upper end of the resistance 79 so that the voltage applied to the anode 53 is as much lower as that of the anode 71 as is the voltage produced in the resistances 77 and 79.
  • the screening grid 70 has a potential lying between those of the anodes 52 and 71 as it is connected to the connecting point of the resistances 77 and 79.
  • the anodes 19 and 33 of the high frequency tubes are connected to the plus pole through the coils 23, 24 and 41, 42 respectively and through resistances 85 and 86 respectively. The potentials of these two anodes are consequently determined inter alia by the value of the latter resistances.
  • the screening grids 18 and 32 of the two high frequency tubes are connected to different points of the following circuit: plus pole, resistance 77, resistance 79, resistance 39, resistance 22, resistance 21, lead 10, minus pole, so that the positive potential of the grid 32 is always as much higher as that of the grid 18 as is the voltage drop across the resistance 22.
  • the biases applied to the two control grids 17 and 28 which are both connected to the lead 8, can be varied, with the aid of the slider of the resistance 63, said slider being connected to the lead 8.
  • this manner of volume control affords the advantage, that, contrary to the more usual manner in which the heating current is regulated, the volume control is effected without inertia and distortion.
  • the minimum negative grid bias to be applied is obviously equal to the voltage drop in the resistance 62.
  • the detector D acts as first-stage low frequency amplification.
  • the leakage resistance 58 ensures that the average potential of the grid 49 remains equal to that of the cathode 50.
  • a radio receiver including a radio frequency amplifier provided with a plurality of screen grid tubes arranged in cascade, a power supply source, a path, including a resistor of predetermined magnitude, connected between said source and the screen electrode of one of said tubes for maintaining said electrode at a predetermined positive potential, and a path, including a second resistor of predetermined value, connected between the screen electrode of a tube preceding said last named tube and the low potential terminal of said first resistor for maintaining the screen electrode of said first tube constantly higher in potential than the screen electrode of the preceding tube by a value equal to the potential drop across said second resistor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Indication Of The Valve Opening Or Closing Status (AREA)
  • General Induction Heating (AREA)
  • Amplifiers (AREA)
US395824A 1928-09-03 1929-09-28 Wireless receiving set Expired - Lifetime US1872231A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL42747A NL27744C (enrdf_load_html_response) 1928-09-03 1928-09-03

Publications (1)

Publication Number Publication Date
US1872231A true US1872231A (en) 1932-08-16

Family

ID=26259642

Family Applications (1)

Application Number Title Priority Date Filing Date
US395824A Expired - Lifetime US1872231A (en) 1928-09-03 1929-09-28 Wireless receiving set

Country Status (4)

Country Link
US (1) US1872231A (enrdf_load_html_response)
FR (1) FR680148A (enrdf_load_html_response)
GB (1) GB323744A (enrdf_load_html_response)
NL (1) NL27744C (enrdf_load_html_response)

Also Published As

Publication number Publication date
FR680148A (fr) 1930-04-25
NL27744C (enrdf_load_html_response) 1932-09-15
GB323744A (en) 1930-01-08

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