US2248242A - Radio tuning system - Google Patents

Radio tuning system Download PDF

Info

Publication number
US2248242A
US2248242A US312072A US31207240A US2248242A US 2248242 A US2248242 A US 2248242A US 312072 A US312072 A US 312072A US 31207240 A US31207240 A US 31207240A US 2248242 A US2248242 A US 2248242A
Authority
US
United States
Prior art keywords
tuning
inductance
oscillator
circuits
range
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
US312072A
Other languages
English (en)
Inventor
Vernon D Landon
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.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL58891D priority Critical patent/NL58891C/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US312072A priority patent/US2248242A/en
Priority to GB91/41A priority patent/GB546248A/en
Application granted granted Critical
Publication of US2248242A publication Critical patent/US2248242A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H03J3/28—Continuous tuning of more than one resonant circuit simultaneously, the tuning frequencies of the circuits having a substantially constant difference throughout the tuning range

Definitions

  • the present invention relates to radio tuning systems, and has for its primary object to provide an improved tuning system of the character referred to wherein two variably tunable circuits having magnetic core Variable inductances are caused to track over a predetermined tuning range.
  • FIG. 1 is a schematic circuit diagram of a tuning system embodying the invention.
  • Figure 2 is a similar schematic circuit diagram showing a modification of a portion of the circuit of Fig. 1, also embodying the invention.
  • Fig. 1, 5 is a tuning inductance of the solenoid type for the antenna or R.-F. stage of a superheterodyne receiver and 6 is a similar oscillator tuning inductance arranged to be tunable conjointly with the first named inductance over a predetermined variable tuning range or a plurality of such ranges by means including a movable magnetic core I in the R.-F. stage inductance and a movable magnetic core 8 in the oscillator tuning inductance joined or connected as indicated by the dotted connection 9, in a manner to move jointly in unison. Additional means hereinafter referred to, such as shunt capacitors for the inductances, further determine the ranges of the inductances 5 and 6.
  • the problem in tracking two or more variable tuning circuits involves the lining up or frequency adjustment of the circuits at not only the high and low frequency ends of the tuning range, but also at one or more intermediate points between the ends of the tuning range.
  • the tuning of the two or more circuits by unitary control means involvescovering differing frequency ranges in the several circuits.
  • the oscillator may have a lower ratio of frequency ranges to cover than the R.-F. stage and in order to track properly a tuning system may require the use of means for modifying the rate of change of inductance in one or the other of two or more simultaneously variable tuning circuits.
  • variable tuning ranges are provided between two circuits, such as the R.-F. and oscillator circuits of a superheterodyne receiver covering a lower band of frequencies and a higher band of frequencies, such as the normal broadcast and short Wave bands
  • the circuits may be made to track effectively over the high frequency range with an oscillator inductance coil only slightly greater in diameter than the R.F. coil, and over the 10W,- frequency range by utilizing an oscillator tuning inductance of considerably larger diameter than the R..-F. tuning inductance.
  • the tracking in the mid-tuning portion of the range is corrected if a portion of the oscillator coil, preferably at the entering end of the coil, with regard to the core, is shunted by a capacitor, the value of which is adjusted to bring the tracking of the two circuits into alignment in that portion of the variable tuning range.
  • the diameters of the two coils may be made the same and a small fixed inductance may be inserted in series with the oscillator inductance.
  • the added series inductance produces about the same effect in shortening the oscillator tuning range than an increase in oscillator coil diameter would have produced.
  • the oscillator coil 6 is only slightly larger in diameter than the R..-F. coil 5, so as to track over a high frequency range.
  • the required reduction in range is accomplished by inserting a series inductance as shown and de-' scribed hereinafter.
  • the inductances 5 and 6 are provided with suitable capacitors and switching means whereby they may be adjusted for tuning through the high and low frequency ranges referred to, also as hereinafter pointed out, and are connected in circuit with a mixer or converter tube In having a signal input grid ll connected to the high potential terminal l2 of the R.-F. inductance 5 and an oscillator grid l3 connected with the high potential terminal 14 of the oscillator inductance 6 through the usual grid leak and capacitor I5.
  • the entering end of the inductance for the core 1, which is the low potential end of the inductance, is provided with a terminal l8 connected to ground or chassis IT as is also a corresponding terminal I8 on the inductance M.
  • the R.-F. or antenna circuit is provided with a shunt capacitor 2i) and a series capacitor 2! in circuit with an antenna or signal collector 22.
  • Connections with the capacitors 2G and 2i are provided by switches 23 and 24 arranged to be operated conjointly, as indicated by the dotted connection 25.
  • Each of the switches is provided with an alternative connection whereby, for the low frequency tuning range, a capacitor 25 of higher value is placed in series with the antenna and a capacitor 25 also of higher value is placed in shunt with the inductance 5 to add capacity for the lower tuning range as provided by the movable core 7.
  • a pair of series connected capacitors 27 and 28 across the inductance 6 provide a tap connection 29 for the oscillator cathode 38 and, in addition, provide for tuning the oscillator circuit at the high frequency end of the tuning range. Movement of the core 8 into the coil 6 lowers the frequency response of the oscillator circuit.
  • a desired wide tuning range may be covered, but the oscillator may become too high in frequency and thus out .of alignment in the mid-portion of the tuning range.
  • the two inductances 5 and 6 may be of the same length and only slightly different diameter, with the same core material and size of core as for tuning through the low frequency range.
  • the oscillator inductance in the present case or the inductance of the circuit having the lower tuning range is increased in diameter as indicated at M, Fig. 2, sufficiently to change the rate of tuning variation to that which is proper for maintaining the circuits in alignment with unicontrol movement of the several cores.
  • the diameter of the winding 6a in Fig. 2 is determined by the shape and length of the core 8 which may be the same as in Fig. 1. In any case, the diameter of the two windings 5 and 5a difier by an amount sufficient to provide tracking between the two tuned circuits when simultaneously tuned by magnetic or other suitable movable cores which are moved by uni-control means.
  • the desired tuning range will be provided by the oscillator, with the oscillator frequency slightly high in the mid-tuning range to produce a predetermined intermediate frequency. This is corrected by the shunt capacitor 33 across a portion of the winding at the entering end of the winding, which as used herein refers to the end of the winding which the core enters and leaves in tuning.
  • the windings 5 and 6 of Fig. l and the winding'Ga in Fig. 2 may be shunted by additional capacitors or capacitors of higher or lower values to produce a second tuning range at a lower mean frequency.
  • additional capacitors or capacitors of higher or lower values are provided in the present example by the capacitors 25 and 26 across the R.-F. coil 5 and by capacitors 35 and 36 connectable across the capacitors 21 and 28 in the oscillator circuit by a switch 31 when moved to the alternate position from that shown in the drawing, closing contacts 38 and 39 with a lead connection 4!] for the cathode circuit 4
  • a switch 42 operable jointly with the switch 3'! serves to connect an additional capacitor 43 in parallel with the capacitor '33 across the tapped portion of the oscillator co-il thereby to correct the tuning and alignment of the oscillator with the R.-F. circuit in the midrange of the low frequency tuning band.
  • the switching arrangement of Fig. 1 adapts the tuning system for receiving signals in a high frequency range, such as the short Wave band and in a second lower frequency range, such as the present broadcast band, by increasing the values of the shunting capacitors of the oscillator and R.-F. circuits and by inserting a small inductance in series with the oscillator coil which approximately permits tracking in substantially the same manner as; with a tuning inductance in the oscillator of greatly increased diameter which would otherwise be required to provide proper tracking between the two circuits in the lower frequency band;
  • the tuning range was changed by increasing the tuning capacitors approximately 10 to 1.
  • the capacity at 2'! from grid to cathode, the capacity at 28 from cathode to ground, and the capacity at 33 from the tap to ground are increased by the addition of capacitors 35, 36 and 43, respectively.
  • the additional cathode to ground capacitor 36 is adjusted for optimum oscillator operation by providing the proper feedback.
  • the additional capacitor 35 from grid to cathode chiefly affects the tuning range, and the capacitor 43 on the tap connection is adjusted to av value resulting in best tracking in the mid-range of the low frequency tuning band.
  • the series inductance M is in series with the grid-cathode capacitor 35 and makes it unnecessary to change the diameter of the oscillator coil for the lower frequency tuning band while securing good tracking throughout the tuning range of the oscillator.
  • the rate of change of frequency with core movement varies rapidly as the coil is just entering the coil or winding and also when the core is substantially completely in the coil.
  • tuning inductance or coils of different diameters in the several circuits such as the R.-F. and oscillator circuits, as hereinbefore referred to, the variation in frequency differs and tracking in the extreme limitation of a tuning range in any band of frequency may be improved by a slight shortening of the length of one of the coils and a slight axial shift in position.
  • the rate of change of frequency at the entering end of the tuning inductance of any of the uni-controlled circuits may be increased or :changed by tapping the inductance winding in spaced relation to the entering end and connecting a capacitor of a predetermined value between the tap and the said end of the winding, and the tracking of any two circuits may be improved by increasing the diameter of one of the variable inductance windings in the tuning circuits while utilizing substantially the same cores, that is of the same material and shape in each of the two windings for lower cost of production.
  • the cathode of the oscillator is connected to ground I! through an indulctance winding ti and a cathode resistor 48 for the purpose of providing a high impedance path to ground for R.-F. currents while maintaining the D.-C. impedance that of the cathode resistor.
  • This forms no part of the present invention.
  • the output circuit of the oscillator comprising the anode 49 and the intermediate output transformer 50 is conventional and requires no further description.
  • a radio tuning system the combination of two tunable signal circuits each comprising an inductance winding, similar magnetic tuning cores for said windings adapted to enter one end of each winding and to move therethrough, thereby'to provide variable tuning of said circuits, uni-control means for moving said cores conjointly in predetermined relation to each other, thereby to cause tracking in the tuning of said circuits, and a capacitor connected in shunt with a portion of at least one of said windings adjacent the entering end thereof with respect to the core movement to improve the tracking of said circuits in a predetermined portion of the tuning range of said system.
  • a radio tuning system the combination of two tunable signal cincuits each comprising an inductance winding, means providing a shunt capacity across each of said windings for turn ng said circuits each to a predetermined frequency, similar magnetic tuning cores for said windings adapted to enter one end of each winding and to move therethrough, uni-control means for moving said coresconjointly, and means providing capacity in shunt with a portion of at least one of said windings adjacent the entering end thereof with respect to core movement for causing improved tracking of said circuits in a midfrequency range, one of said windings being of a larger diameter than the other for further improving the tracking of said circuits throughout a predetermined frequency range including said mid-frequency range.
  • the combination of two tunable signal circuits each comprising an inductance winding, means providing a shunt capacity across each of said windings for tuning said circuits each to a predetermined frequency, similar magnetic tuning cores for said windings adapted to enter one end of each winding and to move therethrough, one of said coils being displaced with respect to the entering end of the core associated therewith, uni-control means for moving said cores conjointly into and through at least a portion of saidpoils, means providing capacity in shunt with a portion of at least one of said windings adjacent the entering end thereof with respect to core movement for causing improved tracking of said circuits in a midfrequency range, one of said windings being of a larger diameter than t e other for further improving the tracking of said circuits through a predetermined frequency range including said mid-frequency range.
  • a tunable signal circuit having a tuning inductance comprising a solenoid coil provided with a movable magnetic core tuning element, of an oscillator circuit comprising a second tuning inductance comprising a second solenoid coil of larger diameter than said first coil, a second like movable magnetic core tuning element for said last named inductance adapted to enter one end of the said inductance in the tuning movement of the core element, and a capacitor connected in shunt with a portion of the second tuning inductance adjacent to said end.
  • a tunable signal circuit having a tuning inductance provided with a movable magnetic core tuning element, of an oscillator circuit comprising a second tuning inductance, a second like movable magnetic core tuning element for said last named inductance adapted to enter one end of the said inductance in the tuning movement of the core element, means providing a capacity connected in shunt with a portion of the second tuning inductance adjacent to said end, for tracking said circuits in a predetermined portion of the tuning range thereof.
  • a radio tuning system the combination of two tunable signal circuits each comprising a tuning inductance provided by a solenoid coil, one of said coils being of larger diameter than the other, similar magnetic core tuning elements for said coils adapted to be moved conjointly and to enter one end of each winding, thereby to vary the tuning of said circuits through predetermined frequency ranges, the difference in diameter of said coils providing for tracking said circuits over the tuning range thereof with a predetermined uniform frequency difference, and a capacitor connected in shunt with a portion of the coil of larger diameter adjacent the entering end thereof, said capacitor having a value such that the tracking of said circuits in a midportion of the tuning range is caused to conform with the tracking of said circuits throughout the remainder of the tuning range thereof.
  • a tunable signal circuit having a tuning inductance of the solenoid type provided with a movable magnetic core tuning element, of an oscillator circuit comprising a second tuning inductance of the solenoid type, a second like movable magnetic core tuning element for said last-named inductance adapted to enter one end of the said inductance in the tuning movement of the core element, means providing a capacity connected in shunt with a portion of the second tuning inductance adjacent to said end, means providing a tuning capacity for each of said indwctances connected in shunt therewith, a third tuning inductance, and means for simultaneously increasing the value of said lastnamed capacities and said first-named capacity and inserting said third tuning inductance in series with said second tuning inductance, thereby to change the tuning range of said circuits by a predetermined amount.

Landscapes

  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
US312072A 1940-01-02 1940-01-02 Radio tuning system Expired - Lifetime US2248242A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
NL58891D NL58891C (sh) 1940-01-02
US312072A US2248242A (en) 1940-01-02 1940-01-02 Radio tuning system
GB91/41A GB546248A (en) 1940-01-02 1941-01-02 Improvements in or relating to electric tuning systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US312072A US2248242A (en) 1940-01-02 1940-01-02 Radio tuning system

Publications (1)

Publication Number Publication Date
US2248242A true US2248242A (en) 1941-07-08

Family

ID=23209757

Family Applications (1)

Application Number Title Priority Date Filing Date
US312072A Expired - Lifetime US2248242A (en) 1940-01-02 1940-01-02 Radio tuning system

Country Status (3)

Country Link
US (1) US2248242A (sh)
GB (1) GB546248A (sh)
NL (1) NL58891C (sh)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2417182A (en) * 1942-10-24 1947-03-11 Rca Corp Short-wave permeability tuning system
US2427331A (en) * 1941-08-16 1947-09-09 Hartford Nat Bank & Trust Co Tuning device comprising at least two tuning circuits having an unequal frequency range
US2486152A (en) * 1940-12-05 1949-10-25 Hartford Nat Bank & Trust Co Unicontrol permeability tuning device for superheterodyne receivers
US2486986A (en) * 1943-06-28 1949-11-01 Rca Corp Permeability tuning system
US2565261A (en) * 1948-09-11 1951-08-21 Rca Corp Permeability tuning system for superheterodyne receiver
US2687514A (en) * 1948-08-27 1954-08-24 Rca Corp Two-band tuning network
US2882392A (en) * 1955-03-09 1959-04-14 Rca Corp Receiver tuned by inductors with tracking by initial positionment of coils on cores
DE974133C (de) * 1943-06-08 1960-09-22 Georg Von Dipl-Ing Schaub Induktive Abstimmanordnung mit Kernverlagerung

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486152A (en) * 1940-12-05 1949-10-25 Hartford Nat Bank & Trust Co Unicontrol permeability tuning device for superheterodyne receivers
US2427331A (en) * 1941-08-16 1947-09-09 Hartford Nat Bank & Trust Co Tuning device comprising at least two tuning circuits having an unequal frequency range
US2417182A (en) * 1942-10-24 1947-03-11 Rca Corp Short-wave permeability tuning system
DE974133C (de) * 1943-06-08 1960-09-22 Georg Von Dipl-Ing Schaub Induktive Abstimmanordnung mit Kernverlagerung
US2486986A (en) * 1943-06-28 1949-11-01 Rca Corp Permeability tuning system
US2687514A (en) * 1948-08-27 1954-08-24 Rca Corp Two-band tuning network
US2565261A (en) * 1948-09-11 1951-08-21 Rca Corp Permeability tuning system for superheterodyne receiver
US2882392A (en) * 1955-03-09 1959-04-14 Rca Corp Receiver tuned by inductors with tracking by initial positionment of coils on cores

Also Published As

Publication number Publication date
GB546248A (en) 1942-07-03
NL58891C (sh)

Similar Documents

Publication Publication Date Title
US2255680A (en) Variable permeability tuning system
US2215775A (en) Radio receiver
US2140770A (en) Electrical coupling device
US2248242A (en) Radio tuning system
US2173898A (en) Radio signal receiving system
US2263613A (en) Unicontrol variable inductance tuning system
US2882392A (en) Receiver tuned by inductors with tracking by initial positionment of coils on cores
US2359684A (en) Loop input system for radio receivers
US2417182A (en) Short-wave permeability tuning system
US2728818A (en) Signal transfer networks for multirange high-frequency radio or television systems
US2816222A (en) Mixing circuit for superheterodyne receivers
US2843683A (en) Television tuner input circuit
US2209982A (en) Oscillator tuning system
US2355470A (en) Multiband receiver circuit
US2259003A (en) Image rejector circuit
US2312211A (en) Tuning system
US2038294A (en) Coupling system
US2074896A (en) Antenna system for multiband radio receivers
US2037754A (en) Superheterodyne receiver
US2486986A (en) Permeability tuning system
US2145371A (en) Oscillator coil system for low frequency bands
US2244177A (en) Signal collecting system for radio receivers
US2201938A (en) Image rejector circuit for radio receivers
US1881284A (en) Wave signaling system
US2475032A (en) Variable permeability tuning system