US2486692A - Device for the band-spread tuning of radio apparatus - Google Patents

Device for the band-spread tuning of radio apparatus Download PDF

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Publication number
US2486692A
US2486692A US664724A US66472446A US2486692A US 2486692 A US2486692 A US 2486692A US 664724 A US664724 A US 664724A US 66472446 A US66472446 A US 66472446A US 2486692 A US2486692 A US 2486692A
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United States
Prior art keywords
tuning
band
series
bandspread
condenser
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Expired - Lifetime
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US664724A
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English (en)
Inventor
Heem Jan Van Der
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.)
Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/02—Details
    • H03J3/10—Circuit arrangements for fine tuning, e.g. bandspreading

Definitions

  • bandspread tuning Different methods of obtaining bandspread tuning are known.
  • a very commonly utilized method involves a circuit arrangement having a xed condenser, a variable condenser and a coil connected in parallel.
  • the range to be covered with bandspreading is determined by the fixed condenser in the coil, and bandspread tuning is effected by means of the variable condenser connected in parallel with the xed condenser.
  • bandspreading may be effected by means of a system of condensers connected in parallel with the fixed condenser, one of the said condensers being variable.
  • the ranges in which bandspread tuning has to be eiiected are chosen in this case by switching-in another tuning coil.
  • the percentage capacity variation obtained by means of the variable bandspread condenser is equal in each bandspread range so that for eachof these ranges the percentage frequency variation is also equal. Since, however, the stations operate at a constant frequency separation, viz. of 9 kilocycles per second for broadcaststations, the scale distances between the stations become, in spite of the equal percentage frequency va'riation in all bandspread ranges, smaller as the bandspread range is located higher in the frequency spectrum.
  • scale distance is to be construed as the number of dial divisions of the tuning indicator between two stations operating in channels located side by side. In other words: the spreading obtained between the stations decreases for stations operating at the higher frequencies so that the accuracy of adjustment also decreases.
  • the invention provides a device with the aid of which it is possible to have equal scale distances between stations operating in adjacent channels for all of the ranges to be spread. According to the invention, this is achieved by connecting an inductor having a suitable inductance value in 4 Claims. (C1. Z50-40) series with each of the condensers of the system with which the capacity variation is effected. v
  • Fig. l represents the basic embodiment ofthe invention
  • Fig. 2 represents a further and more complicated embodiment
  • Fig. 3 shows diagrammatically a practical form of construction of part of the circuit arrangement according to the embodiment of Fig. 2.
  • a tuning condenser I which, together with any of coils 2, 3, 4, which are switched into circuit by means of a switch 5, aiords tuning in a frequency range over which it is desired to tune by bandspreading.
  • a bandspread condenser is connected, in series with a coil 'I, in parallel with the tuning condenser I. Due to the reactance of the coil 1 part of the reactance of the bandspread condenser 6 ⁇ is made inoperative, as it were, which is manifested by the fact that the capacity variation obtained with the aid of the system I, 6, 1, is smaller than the variation which would be obtained with the aid of the system I, 6.
  • the iniiuence of the coil 1 is greater as the frequency is increased, so that in this way the capacity variation obtained by means of the bandspread system decreases as the frequency increases.
  • the percentage frequency variation consequently decreases with an increase of the frequency so that with the simple system according to Fig. 1 the absolute frequency variation can be made equal at least in two different bandspread ranges.
  • This system consequently aiords the possibility of obtaining equal scale distances between the stations in two bandspread ranges whilst in an intermediate range the deviation is still tolerable.
  • FIG. 2 The system shown in Fig. 2 comprises condensers 8, I0 and I2 and coils connected in series with each of the said condensers, viz. coils 9, Il and shown in Fig. 3 wherein-ithe--system Fifor-ffthe capacity variation is representedinthe manner shown in Fig. 2.
  • Fig. 2 Here, howeverf'an inductorfQ corresponding to the coil 9 is formed by the wire section Ill-I5, an inductor I
  • ductor I 3' corresponding to theccil.
  • 5-I6-I8 the connecting I-points I5 and I6 being adjustable so that both by displacing these points and by giving the connecting wires a determinedgshape it is possible to adlzlstrf they circuitry: itinY ,-thefrequired: inductance values.
  • circuit arrangement forxband-spnead; tuning overatxpluralityi ifoff frequency: bands, c ccmprisingsacpluralityx of-ffprincipal inductances elements, a circuit combinationcomprisingnarparallelncircuitrand sa;
  • A-series circuit conneicted sin series with each other, saidrparallelf-circuit compricing fz'a :in-rst leg shaving v1a.' series ⁇ connected variablecfba-nd-spread capacitor andra'rstbandspread .adjusting inductance elementzi'and f a; second ⁇ degli havingl seriesngconnected ⁇ .second i capaciter and sa l second -1 band-spread adjusting finductancee eleinent,.;said fseries circuit comprising a third capacitor and 1a third #band-spread adjusting :iinductance oralement, .
  • a circuit arrangement for band-spread tun- *ing over a plurality of frequency bands comrprisingan.inductiy,e branch having a plurality nf V ⁇ .principal inductive elements, a capacitive branch comprising a variable capacitor and a f'rstfi-nductance'connected in a rst series cir- --Lcuit arrangement zand a second capacitor and a second inductanceconnected in a second series cirCuitarrangement, said first and said second series',circuitparrangements being connected in .ifpafrallelfrelationship, and band selecting switch means coupled toV said capacitive branch to selectively connect-the same to said principal inductive 'elements of said inductive branch.
  • .fsAacircuit arrangement for band-spread tuning over a plurality off frequency bands, comprisme .an inductivel branchl yhaving .a plurality ofaprincipal inductive elements,v a ⁇ ,capacitive branchccomprising .a ⁇ variable-capacitor and va rstzzinductance ⁇ connected in a first series circuitgarrangement, asecond capacitor and a second ,inductance connected in,y a second series circuit varrangementdand .a,.third ⁇ capacitor and a tliirdinductance connected .ina third series circuit ,arrangementsaidrst and second series circuitarrangements, being ⁇ connected in parallel circuit arrangement and, said third series circuit arrangementl beingl connected .in .series with said parallel circuit arrangement. and band-selecting switch means coupled Ato,saidcapacitive branch to,.selectve1y connect ,thevlsame to said prinQDal in

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  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
US664724A 1941-07-01 1946-04-25 Device for the band-spread tuning of radio apparatus Expired - Lifetime US2486692A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL228559X 1941-07-01

Publications (1)

Publication Number Publication Date
US2486692A true US2486692A (en) 1949-11-01

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US664724A Expired - Lifetime US2486692A (en) 1941-07-01 1946-04-25 Device for the band-spread tuning of radio apparatus

Country Status (6)

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US (1) US2486692A (en(2012))
BE (1) BE446251A (en(2012))
CH (1) CH228559A (en(2012))
FR (1) FR883669A (en(2012))
GB (1) GB613152A (en(2012))
NL (1) NL57804C (en(2012))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2835813A (en) * 1954-04-26 1958-05-20 Philips Corp Device for fine tuning of a resonant circuit

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH427931A (de) * 1963-11-27 1967-01-15 Imp Rundfunk Und Fernsehwerk G Abstimmanordnung für ultrakurze Wellen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2207254A (en) * 1938-09-08 1940-07-09 Rca Corp Band spread tuning system
US2252100A (en) * 1938-10-13 1941-08-12 Rca Corp Short-wave radio receiver with band-spreading
US2252919A (en) * 1939-01-10 1941-08-19 Lewis D Eckard Multiwave variable resonator
US2402261A (en) * 1942-11-21 1946-06-18 Rca Corp Permeability tuned band-spread circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2207254A (en) * 1938-09-08 1940-07-09 Rca Corp Band spread tuning system
US2252100A (en) * 1938-10-13 1941-08-12 Rca Corp Short-wave radio receiver with band-spreading
US2252919A (en) * 1939-01-10 1941-08-19 Lewis D Eckard Multiwave variable resonator
US2402261A (en) * 1942-11-21 1946-06-18 Rca Corp Permeability tuned band-spread circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2835813A (en) * 1954-04-26 1958-05-20 Philips Corp Device for fine tuning of a resonant circuit

Also Published As

Publication number Publication date
BE446251A (en(2012))
GB613152A (en) 1948-11-23
CH228559A (de) 1943-08-31
FR883669A (fr) 1943-07-12
NL57804C (en(2012))

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