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US3906373A Expired / Lapsed US ⏱️ 0.0 years remaining

Varactor tuning system

Assignee: Zenith Electronics LLC
•
Filing: 1974-09-23
•
Granted: 1975-09-16
•
Expires: 1994-09-23
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Abstract

Abstract A television channel selector includes UHF and VHF tuners each having a varactor as the frequency-determining element. A number of fixed contacts on a rotary switch are respectively associated with different channels in both the VHF and UHF regions of the spectrum; also included on the switch are a pair of selection contacts. Printed on the same substrate which carries the switch contacts are a plurality of resistors which together constitute a voltage divider that has individually different junctions between the resistors connected to respective different ones of the fixed contacts. A fasttuning shaft drives the selection contacts over the fixed contacts. That shaft is detented each time the selection contacts are moved over a chosen number of the fixed contacts. A slow-tuning shaft is coupled through a gear system to the fast-tuning shaft. The slow-tuning shaft is detented in rotational increments that correspond to movement of the selection contacts, through the gear system and the first shaft, from each one of the fixed contacts to the next. The selection contacts read out a voltage from the divider which is fed to the varactors in determination of frequency. For fine tuning, the varactor control voltage is derived from a tap on a potentiometer the opposite ends of which are connected by the selection contacts across selected individual different ones of the resistors in the voltage divider.

Inventors

  • 👤 Melvin C Hendrickson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 03:10
CPC Classifications
H; H03; H03J; H03J5/00; H03J5/02; H03J5/0209; H03J1/00; H03J1/06; H03J1/14; H03J7/00; H03J7/02; H03J7/04; H03J7/08; H03J7/12

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 241 words
A combined UHF and VHF television channel selector comprising: tuning means including a plurality of varactors as the frequency determining elements, the frequency determined being a function of the voltage presented to a respectively terminal of each such varactor; a rotary switch having a predetermined number of fixed contacts respectively associated with different channels in the VHF and UHf television spectra and at least one selection contact movable over respective different ones of said fixed contacts; a voltage divider composed of a plurality of resistors series connected in succession with individually progressive different junctions between said resistors connected to respective differEnt ones of said fixed contacts; means for impressing a D-C potential across said voltage divider; fast-tuning means including a first rotatable shaft coupled to said selection contact for driving the same from each one of said fixed contacts to the next; means for detenting said first shaft each time upon movement of said selection contact successively between a chosen number of said fixed contacts, said number being greater than two slow-tuning means including a second shaft; a gear system mechanically coupling said second shaft to said first shaft; means for detenting said second shaft in rotational increments corresponding to movement of said selection contact, through said gear system and said first shaft, from each one of said fixed contacts to the next; and means for selectively coupling said selection contact to each of said varactors for establishing a tuning frequency.
Claim 2
Dependent Claim 241 words
A combined UHF and VHF television channel selector comprising: tuning means including a plurality of varactors as the frequency determining elements, the frequency determined being a function of the voltage presented to a respectively terminal of each such varactor; a rotary switch having a predetermined number of fixed contacts respectively associated with different channels in the VHF and UHf television spectra and at least one selection contact movable over respective different ones of said fixed contacts; a voltage divider composed of a plurality of resistors series connected in succession with individually progressive different junctions between said resistors connected to respective differEnt ones of said fixed contacts; means for impressing a D-C potential across said voltage divider; fast-tuning means including a first rotatable shaft coupled to said selection contact for driving the same from each one of said fixed contacts to the next; means for detenting said first shaft each time upon movement of said selection contact successively between a chosen number of said fixed contacts, said number being greater than two slow-tuning means including a second shaft; a gear system mechanically coupling said second shaft to said first shaft; means for detenting said second shaft in rotational increments corresponding to movement of said selection contact, through said gear system and said first shaft, from each one of said fixed contacts to the next; and means for selectively coupling said selection contact to each of said varactors for establishing a tuning frequency.
Claim 3
Dependent Claim 41 words
A selector as defined in claim 1, which includes an indicator wheel affixed to said first shaft and having a plurality of channel indicating numbers, corresponding to selection of respective different ones of said fixed contacts, successively spaced around its periphery.
Claim 4
Dependent Claim 22 words
A selector as defined in claim 2, in which said first and second shafts are spaced apart and parallel to one another.
Claim 5
Dependent Claim 16 words
A selector as defined in claim 2, in which said first and second shafts are coaxial,
Claim 6
Dependent Claim 56 words
A selector as defined in claim 2, in which said gear system couples said second shaft to said first shaft through said means for detenting said first shaft and in which, upon operation of said fast tuning means, said means for detenting said first shaft yields without yielding of said means for detenting said second shaft.
Claim 7
Dependent Claim 33 words
A selector as defined in claim 5, in which, upon operation of said slow-tuning means, said means for detenting said second shaft yields without yielding of said means for detenting said first shaft.
Claim 8
Dependent Claim 44 words
A selector as defined in claim 2, in which said VHF spectra has twelve channels and in which said means for detenting said second shaft has a number of detents for one complete rotation of said second shaft which is integrally divisible into 12.

References Cited (Backward Citations)

US3678421A Cited
US3868609A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-09-15 1979-03-17 1979-09-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-09-15 1983-03-17 1983-09-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-09-15 1987-03-17 1987-09-16 $7700.00 Window Closed / Lapsed

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