US3789331A - Vernier tuning means for uhf tuner or the like - Google Patents

Vernier tuning means for uhf tuner or the like Download PDF

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Publication number
US3789331A
US3789331A US00293465A US3789331DA US3789331A US 3789331 A US3789331 A US 3789331A US 00293465 A US00293465 A US 00293465A US 3789331D A US3789331D A US 3789331DA US 3789331 A US3789331 A US 3789331A
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rotor
capacitor
sections
stator
tuner
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US00293465A
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English (en)
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C Miner
E Balash
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Arris Technology Inc
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Arris Technology Inc
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/20—Continuous tuning of single resonant circuit by varying inductance only or capacitance only

Definitions

  • the vernier rotor can generally be similar to the standard rotor in having its sections extend generally at right angles to the axis of rotation, in which case where many channels are to be tuned the individual sections of the vernier rotor may encompass the tuning of a limited plurality of said channels, or the sections of the vernier rotor may comprise extensions thereof extending generally parallel to the axis of rotation thereof, in which case a larger number of individual sections can be provided than with conventional rotors.
  • VERNIER TUNING MEANS FOR UHF TUNER OR THE LIKE The present invention relates to means for achieving vernier control of tuning in tuners such as those designed for use in the UHF reception band.
  • gang condenser means comprising a plurality of rotary variable condensers the rotors of which move simultaneously and overlap their corresponding stator plates to cumulatively progressive degrees. It is necessary that the individual circuits thus simultaneously tuned track one another over the entire range of tuning, that is to say, the variation in capacitance, and hence in tuned frequency, accomplished in each of the circuits should correspond in desired fashion to the variation accomplished in all of the other circuits. In addition, it is usually desired that there be a certain desired relationship between tuned frequency and angular rotation of the operating shaft.
  • the UHF television band in this country contains 70 channels each 6 me. wide between 470 MHz and 890 MHz.
  • the tuner is conventionally of the superheterodyne type using an intermediate frequency 45.75 MHZ., for the visual carrier of the television signal, thus giving rise to the requirement ofa local oscillator range of 517-931 MHz.
  • Recent governmental requirements relating to tuners capable of tuning all seventy of the available UHF channels explicitly and implicitly require tuning accuracies over the large frequency range involved which have not been achievable by prior art approaches. For example, it is required that each channel selected must tune within one-half a channel width of the correct frequency without the aid of manual fine tuning. This involves an accuracy of plus or minus 3 MHz.
  • the UHF band tuning is typically accomplished by the rotation (usually through 180 or less) ofa variable capacitor which terminates a quarter wave or half wave distributed constant transmission line which is the resonant element of either a tube or solid state amplifier or oscillator circuit.
  • the relationship between capacitance of the terminated variable condenser of a resonant transmission line and the frequency to which that line is tuned is quite complex, but to a rough approximation the capacitance varies inversely as the square of the frequency tuned. in UHF tuners it is desirable for the frequency to vary linearly with tuning so that equal angular rotation will generate equal tuning changes, thus providing for tuning from one channel to another by equal angular rotation no matter where those chan nels may be in the UHF band.
  • stator plate or plates have an area or angular extent, considered in terms of the movement of the rotor plate between one tuning extreme and the other, which encompasses substantially the full degree of movement of the rotor plate, the rotor plate being movable from one extreme position where it overlaps the stator plate either not at all or to a minimal degree (minimum capacitance and maximum frequency) to another extreme position in which it overlaps the stator plate to a maximum degree (maximum capacitance and minimum frequency).
  • each segment of the rotor plate moves sequentially into operative engagement with the stator plate as the rotor plate is moved from its position of minimal overlap to its position of maximum overlap, with a segment of the rotor plate once moved into overlapping relation with the stator plate remaining in that overlapping relationship as the rotor plate moves further to its position of maximum overlap.
  • each segment of the rotor plate once it comes into overlapping relationship with its stator plate, acts cumulatively with those segments of the rotor plate which had theretofore overlapped the stator plate and those segments of the rotor plate which thereafter come to overlap the stator plate.
  • the conventional approach to vernier control of capacitance with variable capacitance tuners of the type described is to serrate one or more of the rotor plates into sections and then to bend those sections individually toward or away from the corresponding stator plate. If the section is bent toward the corresponding stator plate it will, when it comes into overlapping relationship therewith, produce a higher capacitance therewith than when it is bent away therefrom.
  • the conventional alignment approach when using a serrated rotor blade of the type described is to start at the high frequency end of the band, when the rotor is at its position of minimum overlap with the stator, adjust the first section of the stator, and move respectively to lower frequencies as succeeding sections come into operative engagement with the stator plate and then adjust those other sections in appropriate fashion. The effects of these adjustments are cumulative in that the total tuning capacity at any point of rotation includes the sum of the effects of each of the adjustments made up to that point on the rotor blade sections overlapping the stator plates.
  • This system has two primary disadvantages first, because the adjustments are effectively cumulative, if, after the alignment is accomplished, an additional correction is needed at some point in the band and a readjustment is made, all frequencies in the band lower than the frequency at which the adjustment is made are affected and it is necessary then to readjust all of those other sections. Second, each section optimizes the tuning for but a single point over a range of frequencies, and hence the degree to which the tuning curve is affected for all frequencies is often far from optimal.
  • a second variable capacitor means electrically connected to the standard capacitor means, but differing therefrom in that the stator plate, instead of having an area or angular extent in the direction of movement of the rotor substantially corresponding to the entire tuning movement of the rotor and therefore to the entire tuning range, in fact has an area or angular extent of much lesser size, corresponding to a single channel to be tuned or to a small plurality of channels to be tuned.
  • the rotor plate of this second capacitor means comprises a plurality of individually adjustable sections each having an area or angular extent in the direction of movement of the rotor, substantially corresponding to that of the stator plate with which it cooperates.
  • each of the individually adjustable rotor sections may be made of sufficient area or angular extent to correspond to a small plurality of the channels to be tuned, to wit, five to seven channels out of 70, and an even greater degree of precision is obtained when the conventional rotor is provided with the usual cumulatively acting adjustable sections, but with the sections on the conventional rotor rotationally staggered with respect to the sections of the vemier rotor.
  • variable capacitor tuner In the usual type of variable capacitor tuner, the rotor and stator blades, parallel to one another, extend in a direction substantially at right angles to the axis of rotation of the rotor blades.
  • the vernier tuning capacitor involved in the present invention may be similarly constructed.
  • a special form of vemier condenser is disclosed in which the individually adjustable sections of the rotor extend in a direction substantially parallel to the axis of rotation of the rotor and are arranged circumferentially around a disk-like support.
  • the present invention relates to the structure and arrangement of a tuning instrumentality as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:
  • FIG. 1 is a top plan view of a section of a tuner constructed in accordance with the present invention showing two tuning circuits such as might be employed for the detector and the local oscillator of a superheterodyne receiver;
  • FIG. 2 is a front elevational view of a convential rotor plate used in the main tuning portion of a given tuning section;
  • FIG. 3 is a front elevational view of the rotor plate used in the vemier tuning section of the tuner of the present invention
  • FIG. 4a is a composite rear elevational view of the conventional rotor plate of FIG. 2 andthe stator plate with which it cooperates, the rotor plate being shown in a position toward the low frequency end of the tuning band;
  • FIG. 4b is a composite rear elevational view of the rotor plate of FIG. 3 and the stator plate with which it cooperates, showing the same relative rotational position as corresponds to that of the rotor and stator plates in FIG. 4a;
  • FIGS. 5a and 5b are views similar to FIGS. 4a and 4b respectively but showing the rotor plates in their respective positions relative to their respective stator plates at a higher tuning frequency than that shown in FIGS. 4a and 4b;
  • FIGS. 60 and 6b are views similar to FIGS. 50 and 5b respectively but showing the parts in the positions which they assume at a still higher tuning frequency;
  • FIG. 7 is a view similar to FIG. 1 but showing a specifically different construction for the vernier tuning capacitor.
  • the invention is here specifically disclosed in connection with a tuner designed to tune all seventy of the channels in the UHF band, that being done because the tuner of the present invention is exceptionally well adapted to meet the tuning requirements there involved, while other tuning arrangements have failed to meet those requirements. It will be appreciated, however, that the invention is not limited to that particular application, but may be applied more broadly.
  • the capacitive tuners have been here disclosed as of the rotary variable type, the terms rotor” and stator” therefore being applied to the relatively movable and stationary parts thereof in conventional fashion, it will be understood that rotary movement of the parts relative to one another is not essential to their operative tuning relationship, nor is it essential that one of the elements stand still while the other moves they both could move, either in the same direction at different speeds or in opposite directions.
  • the terms rotor and stator are used generically, the term rotor” referring to a movable element and the term stator referring to an element which may either be stationary or movable but with respect to which the rotor moves.
  • the tuners are here disclosed as embodied in quarter wave or half wave transmission line structures, that is exemplary only, and they could be used in conjunction with any circuitry or structure by means of which an electrical tuning condition is produced.
  • FIG. 1 is an idealized view on an enlarged scale, of a tuner such as might be employed, in accordance with the present invention, for tuning over the entire seventy channel range of the UHF band. It comprises conductive side walls 2 and partitions 4 which divide the interior structure into compartments 6 and 8 which house the tuning structure for two different circuits, such as the detector and the local oscillator.
  • Each of those individual tuning devices are of the transmission line type, including an elongated conductive element 10 which extends from one end wall of a given compartment 6 or 8 toward the other end wall thereof and spaced from the bottom wall thereof, and which carries at its end a plurality of electrically connected stator plates 12.
  • a shaft 14 which, in each compartment 6 and 8, has rotor plates 16 secured thereto and rotatable therewith.
  • the plates 12 and 16 define a variable capacitor which, in conjunction with the conductor 10 and the walls 2 and 4, define a resonant cavity transmission line the resonant frequency of which is determined by the capacitance defined between the stator plates 12 and the rotor plates 16.
  • the stator plates 12 are of a considerable area and, considering that area in terms of angular rotation about the axis of 14 of the shaft 14, the plates 12 extend about the axis 14 over approximately that being the full extent of rotation of the shaft 14 from one extreme of the tuning range to the other.
  • the rotor plates 16, mounted fast on the shaft 14 by means of the recess 18 formed in the plates 16 which snaps over shaft 14, is likewise of a considerable area, and extends rotationally around the axis 14' of the shaft 14 over approximately 180".
  • Its radially outer edge 16', while curved, is neither circular nor coaxial with the axis 14' the radial extent of the rotor plate 16 varying from one end thereof to the other, this being a well-known and conventional approach to the objective of providing, at least roughly, a desired relationship between tuning frequency and angular rotation of the plate 16, in this case providing for equal frequency changes for a given degree of angular rotation from one end of the tuning range to the other.
  • one or more of the outermost rotor plates 16 in a given section the plates that are not interposed between stator plates 12 but instead are outside one or the other of the end stator plates 12 is provided with a plurality of inwardly extending notches or slots 20, thereby to divide the radially outer portion of the plate 16 into a plurality of circumferentially separated sections 16a-161.
  • Each of these sections 16a-161 may be bent out of the plane of the rotor plate 16 toward or away from the stator plate 12 with which the rotor plate is adapted to cooperate, thereby to trim or adjust the capacitance of the device.
  • the angular locations of the slots 20 in the rotor plate 16 are indicated in terms of the degrees of rotation of the shaft 14 from its maximum clockwise position for low frequency tuning to its maximum counterclockwise position for high frequency tuning.
  • the slot 20 between sections 16a and 16b will come into approximate alignment with the upper edge of the stator plate 12 when the shaft 14 has been rotated 10 degrees from its full counterclockwise position
  • the slot 20 between sections 16b and 16c will register with the upper edge of the stator plate 12 after 23-1/2 degrees of rotation
  • the slot 20 between sections 16c and 16d will come into registration with the upper edge of plate 12 after 37 degrees of rotation, and so on.
  • FIG. 4a illustrates a rotation of the shaft 14 of 45- /2"
  • the slot 20 between sections 16c and 16d has already moved above the upper edge of the plate 12, while the slot 20 between sections 16d and 16e is just beginning to move into registration with the upper edge of the plate 12.
  • the sections 16a, 16b and 16c no longer have any substantial capacitance-producing effect in conjunction with the plate 12, the sections 16e-16l are still fully in capacitance-producing relationship with the plate 12, and the section 16b is par tially in and partially out of capacitance-producing relationship with plate 12.
  • 5A and 6A show the relationship between the rotor plate 16 and its corresponding stator plate 12 for rotations of 80 and 130-/z respectively, the slot 20 between sections 16f and 16g I being in substantial registration with the upper edge of the plates 12 in FIG. 5A, while in FIG. 6A the plate 16 is shown in a position intermediate between registration of the upper edge of the plate 12 with the slot 20 between section 16i and 16j and the slot 20 between sections 16j and 16k respectively.
  • the tuning device in compartment 6 of FIG. 1 is modified in accordance with the present invention in order to provide for the desired tuning and tracking accuracy.
  • an auxiliary stator plate 22 is electrically connected to the stator plates 12, but differs from the stator plates 12, as may clearly be seen from FIG. 4B, in that its angular or circumferential extent is very much smaller than that of plates 12, and, instead of extending around the rotor shaft axis 14' by 180, as is the case with the plates 12, it has an angular extent of only about 15 degrees.
  • the standard stator plates 12 extend all the way to the rotor shaft 14, the stator plate 22 extends only a fraction of that distance toward the shaft 14.
  • a rotor plate 24 Fast on the rotor shaft 14, and cooperable with the stator plate 22, is a rotor plate 24 the outer periphery of which is divided, by slots 26, into a plurality of sections 24a241, each of those sections having an angular extent of approximately 15 except for section 24a, which has an angular extent of approximately 17
  • the angular extent of each of the sections 24a-241 is closely the same as that of the stator plate 22. It will moreover be apparent from FIG. 48 that the extent to which the stator plate 22 extends radially inwardly toward the shaft 14 is roughly commenserate with the radial extent of the sections 240-241.
  • each of the sections 24a-241 will be moved into overlapping capacitance-producing relationship with the stator plate 22 and then moved out of that relationship.
  • section 24d is in capacitance-producing relation with plates 22, sections 240 and 24s and in perhaps peripheral minor capacitance-producing relationship therewith, and all of the other sections of plate 24 are out of capacitance-producing relationship with the plate 22.
  • sections 24f and 24g are each partially in capacitance-producing relationship with plates 22, while the other sections of the plate 24 are not, and when the rotor shaft 14 is rotated to the position shown in FIG. 68 it is section 24j which is in capacitanceproducing relationship with plate 22, sections 24k and 24i are perhaps peripherally in that condition, and the other sections are not in that condition.
  • each of the sections 24a-241 produces with the stator plate 22 a certain amount of capacitance, the particular amount being dependent upon the spacing between the plates when they overlap and hence being adjustable by bending a corresponding section out of the plane of the plate 24 either toward or away from the plate 22.
  • each section will provide tuning control for approximately 6 channels.
  • the sections 24a-241 or rotor plate 24 are disposed around the axis of rotation 14' of the rotor shaft 14 in a staggered manner relative to the sections 16a-16l of the rotor plate 16.
  • the slots 20 separating the rotor sections 160-161 may occur at rotational values of 10, 23 12, 37, 52, 66, 94, 108, 122, 136 k, and l49-% respectively
  • the slots 20 separating the sections 24a-241 may occur at rotational values of I'M/2, 31, 45 /2 ,”5"9-%'',7 f,'8, "1'01 use 13s /2", 144 w and 159 respectively.
  • 13 or 14 individual sections are provided instead of the twelve sections here specifically disclosed by way of example, the actual angular values separating the individual sections will be correspondingly varied, but preferably without departing from the overlapping or alternate arrangement here disclosed.
  • FIGS. 4A and B when a slot 20 on one rotor blade 16 or 24 is approximately in line with the upper edge of its corresponding stator plate 12 or 22, the upper edge of the other stator plate 22 or 12 is located approximately between a pair of adjacent slots 20 on its corresponding rotor plate.
  • the size of plate 22' is of limited angular extent relative to the rotation of the rotor shaft 14, is located radially outside the rotor plates 16, and extends in a direction substantially parallel to that of the rotor shaft axis 14'.
  • the rotor 24 in FIG. 7 comprises a disc or some like part fast on shaft 14 from the periphery of which a plurality of finger-like sections 26 extend, those sections 26 being oriented substantially at right angles to the disc-like portion of the rotor 24 and therefore being substantially parallel to the plane of plates 22' and the axis 14' of the rotor shaft 14.
  • non-cumulativelyacting tuning portion acts to correct residual error in the cumulatively-acting portion and makes for easier adjustment of the cumulatively-acting portion itself.
  • alignment accuracies are achieved which are three times greater than what could be obtained formerly by the cumulative-acting system alone.
  • the tuning arrangement here disclosed can be used whether or not the normal variable capacitor tuning means is provided with adjustable sections such as the sections 16a-161 or not, particularly if the vernier tuning means of FIG. 7 is employed where a large number of individual adjusting sections may be provided. While but a limited number of embodiments of the present invention have been here specifically disclosed, it will be apparent that many variations may be made therein, all within the scope of the instant invention as defined in the following claims.
  • variable capacitor means comprising first and second capacitors each comprising a stator and a rotor, the stators of said two capacitors being directly electrically connected, the rotors of said two capacitors being directly electrically connected and operatively mechanically connected for simultaneous movement over first and second given distances respectively to tune over the desired range, said stator of said first capacitor having a dimension extending in the general direction of said movement of said rotor of said first capacitor which at least substantially corresponds to said first movement distance, said rotor of said first capacitor having a dimension extend ing in the said general direction of said movement of said rotor which at least substantially corresponds to said first given distance, said rotor being movable over said first given distance between positions of minimum and maximum operative overlap with said stator, said stator of said second capacitor having a dimension extending in the general direction of movement of said rotor of said second capacitor which is only a minor fraction of said second given distance, said rotor of said second capacitor having a dimension extending in the said general direction
  • said tuner of claim 1 in which said rotor of said first capacitor is divided into a plurality of sections each having a dimension in the general direction of movement of said rotor which is a fraction of the corresponding overall dimension of said rotor and movable sequentially into cumulative operative overlap with their corresponding stator as said rotor is moved from one end of the desired tuning range to the other, the spacing of said sections relative to their corresponding stator while overlapping said stator being individually adjustable.
  • tuner of claim 1 in which said tuner is a UHF tuner designed to tune over substantially the seventy channels of the UHF band, and said dimension of said stator of said second capacitor corresponds to the tuning of about six channels in the UHF band.
  • said tuner of claim 6 in which said rotor of said first capacitor is divided into a plurality of sections each having a dimension in the general direction of movement of said rotor which is a fraction of the corresponding overall dimension of said rotor and movable sequentially into cumulative operative overlap with their corresponding stator as said rotor is moved from one end of the desired tuning range to the other, the spacing of said sections relative to their corresponding stator while overlapping said stator being individually adjustable.
  • said rotor of said second capacitor comprises a member rotatable about an axis and having said sections extending therefrom substantially in the same direction as said axis, the stator of said second capacitor being mounted adjacent said sections to extend in a direction substantially parallel thereto.
  • said rotor of said second capacitor comprises a disk rotatable about an axis, said sections of said capacitor means being defined by fingers arranged circumferentially around said disk and extending therefrom in a direction substantially parallel to said axis, the stator of said second capacitor being mounted adjacent said sections to extend in a direction substantially parallel thereto.

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  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
US00293465A 1972-09-29 1972-09-29 Vernier tuning means for uhf tuner or the like Expired - Lifetime US3789331A (en)

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US29346572A 1972-09-29 1972-09-29

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US (1) US3789331A (enrdf_load_stackoverflow)
JP (1) JPS4976401A (enrdf_load_stackoverflow)
CA (1) CA974616A (enrdf_load_stackoverflow)
DE (1) DE2348978A1 (enrdf_load_stackoverflow)
GB (1) GB1387382A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025882A (en) * 1974-11-18 1977-05-24 Sanyo Electric Co., Ltd. UHF tuner having frequency setting fine toned by varying characteristic impedance of resonant line
US4459702A (en) * 1981-04-16 1984-07-10 Medwin Albert H Electronic vernier
US9722569B1 (en) * 2013-06-12 2017-08-01 Christos Tsironis Multi-band low frequency impedance tuner

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5044254U (enrdf_load_stackoverflow) * 1973-08-24 1975-05-06
JPS5420582Y2 (enrdf_load_stackoverflow) * 1973-08-24 1979-07-25
JPS5148643U (enrdf_load_stackoverflow) * 1974-10-09 1976-04-12

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904165A (en) * 1929-02-18 1933-04-18 Telefunken Gmbh Variable condenser
US2250329A (en) * 1939-08-14 1941-07-22 American Steel Package Company Variable electrical condenser and method of manufacture
US3222668A (en) * 1961-08-16 1965-12-07 Lippel Bernard Capacitive coder
US3292060A (en) * 1966-12-13 Variable capacitor
US3537045A (en) * 1966-04-05 1970-10-27 Alps Electric Co Ltd Variable capacitor type tuner

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3292060A (en) * 1966-12-13 Variable capacitor
US1904165A (en) * 1929-02-18 1933-04-18 Telefunken Gmbh Variable condenser
US2250329A (en) * 1939-08-14 1941-07-22 American Steel Package Company Variable electrical condenser and method of manufacture
US3222668A (en) * 1961-08-16 1965-12-07 Lippel Bernard Capacitive coder
US3537045A (en) * 1966-04-05 1970-10-27 Alps Electric Co Ltd Variable capacitor type tuner

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025882A (en) * 1974-11-18 1977-05-24 Sanyo Electric Co., Ltd. UHF tuner having frequency setting fine toned by varying characteristic impedance of resonant line
US4459702A (en) * 1981-04-16 1984-07-10 Medwin Albert H Electronic vernier
US9722569B1 (en) * 2013-06-12 2017-08-01 Christos Tsironis Multi-band low frequency impedance tuner

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GB1387382A (en) 1975-03-19
DE2348978A1 (de) 1974-04-04
CA974616A (en) 1975-09-16
JPS4976401A (enrdf_load_stackoverflow) 1974-07-23

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