DE1026381B - Broadband tuning device with an adjustable capacitive tuning member - Google Patents

Description

GERMAN

The invention relates to a tuning device, the extremely wide frequency ranges in the VHF and decimeter wave range without band switching able to cover.

According to the invention, a broadband tuning device with a capacitive tuning element that can be adjusted relative to a self-induction element, the adjustment of which causes a change in the effective self-induction of the self-induction element, characterized in that the tuning member and the self-induction coil, preferably concentrically, are arranged in a housing, for a (high-frequency.) part of the trajectory of the Tuning member the same with the housing forms a cavity resonator, while for the other (lower frequency) part of the trajectory the vote. First and foremost by changing the effective. Inductance of the coil takes place.

This tuning device allows tuning over an extremely wide frequency range, for example the usual television frequencies between 54 and 890 megahertz, and has an extremely high quality factor at the upper end of the frequency range, with the transition from coil resonance to Cavity resonance is automatic, continuous and without band timing circuit is going on.

Furthermore, the input and output terminals can be tinge-grounded, so that the tuning device particularly is well suited for use in oscillator circuits Gd.

It is a broadband tuning device is known in which a capacitance tuning member along a Coil is movable that the effective part of the tuning device in the upper frequency range Lecher line forms, while in the other tuning positions the reactance essentially caused by concentrated inductances.

In the drawings the invention is illustrated by way of example, namely FIG

Fig. 1 shows a first embodiment of a tuning device according to the invention, namely in Longitudinal section along the line 1-1 in Fig. 2,

FIG. 2 is an end view of the tuning device according to FIG. 1,

Fig. 3 is a cross section along the line 3-3 in Fig.l,

FIG. 4 shows a cross section through a coil from the tuning device according to FIG. 1 in a larger one Scale,

Fig. 5 a. Circuit diagram of a heterodyne receiver with two tuning devices of the in Fig. 1 shown type,

Fig. 6 shows a second embodiment of a broadband tuning device with a
adjustable capacitive tuning element

Applicant:

Aladdin Industries, Incorporated,
Nashville, Tenn. (V. St. A.)

Representative: Dipl.-Ing. KA Brose, patent attorney,
Pullach near Munich, Wiener Str. 1/2

Claimed priority:
V. St. ν. America June 21, 1954

Harold T. Lyman Jr., Milford, Conn.

and Francis Mason, Westport, Conn. (V. St. Α.),

have been named as inventors

tuning device according to the invention in longitudinal section along the line 6-6 in Fig. 7,

7 and 8 are cross-sections along lines 7-7 and 8-8 in FIGS. 6 and

FIG. 9 shows a cross section through the coil from FIG Tuning device according to Fig. 6 on a larger scale.

The tuning device 1 shown in Fig. 1 for high frequency covers an extremely wide area Frequency range, approximately from 54 to 890 megahertz.

To vote on - the upper part of theirs Frequency range is the tuning device with an elongated, conductive "metallic housing 2 provided that as a multiple contiguous cavity resonator for a quarter wave resonance Frequencies between 470; and 890 megahertz (decimeter waves) is effective. The illustrated housing 2 is at the opposite ends with end walls 3

and 4 provided. :

A conductive mandrel 5 is .axially mounted in the housing 2, which acts as a resonator, in such a way that it is in high-frequency connection with the end wall 3, for example through direct conductive contact.

In order to produce resonance at relatively low frequencies (in the VHF range), im is Inside the housing 2, a coil 6 is arranged coaxially with the mandrel 5. In the case of the coil shown is the one end section, 7 of the same directly

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the outer end of the dome 5 is connected. Both the Mandrel 5 as well as the coil 6 'can consist of metal on an insulating tubular Carrier 8 (Fig. 3 and 4) is deposited or formed in another way. A thin layer 9 a low loss dielectric material can be applied over the coil 6 and the mandrel 5 to to isolate these parts and to. protection.

The voting device 1 is by means of a

coupled, and the inner narrowed portion 11 of the sleeve is capacitive to the right end of the coil 6 coupled. Accordingly, the entire coil 6 is effective between the ring 16 and the housing 2 switched on. The resonance arises from the inductance of the coil and the capacitance between, the sleeve 10 'and the spool 6 and between the sleeve 10 and the ring 16 in connection with the capacity between, the ring 16 and the housing 2 and the

Elongated tuning member 10 tuned between io others, distribute and circuit capacities.

the coil 6 and the housing 2 can be moved relatively. By moving the sleeve 10 to the left, a

is ordered and which is formed in the illustration as an elongated sleeve 10, which is telescopic over the Coil 6 and the mandrel 5 can grip such that

progressive enclosing of the coil 6 by the sleeve and a shortening of that part of the coil, the effective between the ring 16 and your

these parts can be enclosed by the sleeve. 15 housing 2 is switched on, causes. The part of The illustrated sleeve 10 slides on. her left coil 6, which is enclosed by the sleeve 10, is

End portion 11 in a fairly tight sliding fit over the coil 6 and the mandrel, 5.

For part of the voting range, it is the voting one Ring 12j in or around an axial Opening 13 in the end wall 4 of this housing 2 is attached is in direct contact with the front wall 4.

Insulation in the form of a coating on a reinforced part 14 is provided between the sleeve 10 ¹ and the ring 12 in order to provide a capacitive energy transfer between the ring 12 and the sleeve

effectively short-circuited or at least heavily loaded and is decoupled from the part of the coil between the sleeve and the housing 2. The energy transfer to and from this device takes place through the sleeve IO ^{1 to a} large extent any effect on the functioning of the tuning device as a result of secondary resonances in the switched-off part of the coil 6 by means of a coupling member in the form of a coupling element. The resonance frequency of the tuning device increases steadily to the extent that the sleeve 10 surrounds the coil 6-. Continued movement of the sleeve 10 ^; to the left under certain circumstances leads to a complete enclosure of the coil 6. If the coil is made ineffective in this way, the housing 2 is able to resonate 10, when the sleeve is moved to the left 30 as a multi-contiguous quarter-wave. The ring 12 thus serves to couple the resonance cavity, which through the effective capacitance of the sleeve 10 with the end wall 4 of the cavity at the between the end walls 3 and 4 due to the upper end of the tuning range of the tuning pre-influence of the ring 12, the sleeve 10 · and of the cathedral 5 direction 1. is loaded. In reality, the housing 2 begins the

Provide to accept a transfer of energy to the sleeve IO ¹ with comparable 35 characteristics of a cavity resonator, proportionate low frequencies, is before the coil 6 is completely enclosed, so · that a gradual addition of the sleeve 10 'and spaced from the couplings junction ¹ of the coil resonance to the lung ring 12 a second energy transfer member cavity resonance takes place.

arranged, which in this case has the shape of a longitudinal When the sleeve 10 approaches the point in which

Borrowed coupling sleeve 16, which completely encloses the coil 6 outside of the 40, the housing 2 goes at a distance from the ring 12 and in, the thicker section 14 of the sleeve 10 from the coupling axis direction is aligned with this through an insulating ring 16 to the coupling ring 12 over. When the tube 17 is held, the ^{sleeve 10 attached to the 1} ring 12 reaches the point where it is the coil 6. In the right part of the range of motion that completely encloses the enlarged section 14, the entire sleeve 10 moves, its reinforced section 14 moves in 45 into the ring 12. By moving further inside the coupling sleeve 16 and is thus capacitive towards the sleeve 10: the widened section is coupled to the same on the left. 14 pulled out of the ring 12 so that the capacitance

The sleeve 10 can be placed along the spool 6 and between dam; Ring and the sleeve 10 'decreases. Doms 5 by means of a cam or a cam, - As a result, the capacitive load between Disk 18 are moved on a rotatable 50 the end walls. 3 and 4 of the cavity 2 ver-rule shaft 19 is attached. A flexible insulation reduces the resonance frequency of the cavity

rod 20 connects the sleeve 10 with a pivot at. a cam follower arm 22 which carries a roller 23, which by a tensioned spring 24 against the Cam 18 is pressed.

At the right end of the tuning sleeve 10 an insulating tube 25 can be attached in such a way that it can slide in the ring 16 and guide the sleeve when it increases accordingly at the left end of its movement. It should be noted that the
Capacity between the ring 12 and the sleeve 10
and the mandrel 5 lies. Accordingly, the
capacitive loading of the cavity if: the
Capacity between the ring 12 and the sleeve 10
is reduced even if the capacity is between
the mandrel 5 and the sleeve 10 simultaneously thereby
may be increased by a certain amount that the

area is located. The flexible rod 20 can be progressively enclosed at 60 dona 5. Be fastened to the top of a disk 26 which is mounted inside the insulating tube 25 serving ^{the end of the guide covered by 1 of the tuning device.}
Aligning longitudinal slots 26 a, 26 b and 26 c are used

the passage of the. Arm 22 and allow its free

Frequency range, the extended section 14 of the sleeve 10 is pulled completely out of the ring 12 and the sleeve 10 is completely in. the housing of the movement between the two positions, which in 65 cavity shaver.

Fig. 1 fully extended, and are shown in dashed lines. At comparatively low frequencies can

When the sleeve 10 and the arm 22 are in power to and from the tuning device 1 Fig. 1 is in the fully extended position, is by connecting a line 27 to the greed Reinforced portion 14 of the sleeve 10 capacitively transmitted with the transmission ring 16, are. The administration the ring 16 70 27 used for energy transmission leads to a terminal 28, which acts as an input terminal

5 6

For a television band of very high frequency, ring 16 is automatically removed from the circle and

can. the coupling loops 29 and 32 automatically to

At higher. Frequencies, roughly those of a television effect.

The tuning device 1 can be used in various transmissions to the tuning device 1 by means of 5 types of circuits or circuits using an input coupling loop 29, which are used in those in which a vote is desired. Housing 2 of the resonator is arranged. The Loop As an example, Fig. 5 shows a device 36 which is an over can with input terminals 30 and 31 for ultra high position receivers and two such frequencies connected. Includes size and location of tuners that the sub-ticket loop 29 can be changed so that Somehow io dung α 1 and are designated b 1 wherein the Abeine desired impedance between the terminals 30 ¹ tuning device la with the tuner 1 and 31 provided, it is, and also matches that of the coupling and the tuning means 1 b some degree of the input circuit with the resonant cavity changed is the device 36 has a high frequency is changed, whereby the frequency bandwidth of the amplifier stage 37, a triode is controlled in lattice energy transferred 38th 15 basic circuit containing a cathode 39, a cathode heater 40, an anode 41 and a grid 42 through the tuning device 1 by means of an output coupling loop 32 connected to ground by a line 43, which takes place at ultra-high frequencies, which is connected to the is one. The output terminal 33 of the tuning device end is connected to an output terminal 33 ', 1 α is directly connected to the cathode 39, while the other end by means of: a feed-through 20 an aperiodic choke 44 and a. Resistor 45 approximately capacitor 34 led out of the housing 2 in series between the cathode 39 and earth and with the ring 16 and the input terminal. 28, the resistor 45 being connected by a con by means of a line 35. The capacitor 46 is bridged to earth. In order to prevent an active guide condenser 34 causing a small capacitive grounding of the cathode 39 through the filament 40 between the end of the coupling loop 32 and 25, aperiodic chokes 47 are connected to the housing 2 and can thus be connected to a small filament in Connected in series.

Capacitor to be replaced; that is between the line the input terminals. 30 and 31 of the voting

35 and the housing is switched on. At ultra-high direction 1 α can by means of a transmission line

The capacitor 34 has a low frequency 48 connected to a decimeter wave antenna 49

Impedance and thus effectively grounds the terminal lead 30. A special antenna 50 for ultra-short waves

35 of the coupling loop 32. the resonator housing 2. is shown with corresponding antenna

At these frequencies the loop operates. 32 connecting terminals 51 and 52 are connected. Two coils

Energy output through the tuning device 1. 53 and 54 form the primary windings of the

In the lower, end of the frequency range, it is used for balancing and impedance matching

Tuning device 1 are the loop 29 and the 35 transformers 55 and 56>, which also have secondary

gaugsschileife 32 largely ineffective for the windings 57 and 58. One end of the

Energy transfer to and from coil 6 or winding 57 is grounded and the other end is

at least unsuitable means for the energy transmission directly with the input terminal 28 for VHF

supply. At these lower frequencies, energy is connected to the tuning device la . In the case of the

through line 27 from input terminal 28, for 40 secondary winding 58, one end is also grounded.

VHF frequencies to the ring 17 and from there the sleeve. A compensation capacitor 59 connects the other

10 and. the coil. 6 supplied. Energy is from the end of winding 58 with earth. A coil 60 and

Ring 16 of the output terminals 33 by means of the coupling an adjustable capacitor 61 are in series

loop 32 fed only as an extension between each of terminals 51 and 52 and ground

the line 35 acts. In. the lower one, the VHF-45, to serve as a series resonance trap.

Frequencies corresponding end of the frequency The heterodyne receiver 36 contains a mixer

range, the capacitor has a relatively level 62, in which the tuning device 1 b

high impedance and is therefore unsuitable for the line located. The energy transfer from the high frequency

35 to be bridged to earth or ground. The sequence amplifier stage 37 to the tuning device 1 b

The voice effect in the range of the VHF frequencies 50 takes place by means of an additional tuning device

goes back to the parallel resonance of the impedance 63, which has a coil 64 which is axially in a

of the uncovered part, the coil 6 and the mandrel 5, sleeve 65 is attached and by means of a piston 68

with the capacitance of the capacitor 34 and the can be matched to. The piston consists of

Terminal 28 connected outer circuit. a perforated disc 71 and rings 69 and 70.

For the higher frequency section of the tuning 55 Through the piston. 68 becomes the part of the coil 64

area, the sleeve 10 from the coupling ring in. The sleeve 69 is effective: grounded, so that only the part

16 pulled out with the result that the ring 16 of the coil 64 between the sleeve 69 and the anode

effectively switched off by the tuning device 41 in. The output circuit of the amplifier tube 38 for

is, while it also passes through the capacitor 34 effect,

is effectively earthed. 60 For the energy transfer from the tuning

It can now be seen that by changing the device 63 in the decimeter range, an off setting of the tuning device 1 is an automatic coupling loop 72 in the housing 65 of the actuator transition from a set of input and tuning devices next to the coil 64 and output circuits to one Another set causes the input coupling loop 296 to pre-tune. This transition is made by frequency selection 65 direction 1 b connected, for the energy transfer and by advancing the sleeve 10 from the to the tuning device 16 in which the lower elongated ring 16 to the ring 12. In the lower frequencies encompassing. A section of the tuning range covered by the end of the frequency range connections to transducers 36 is established between the ring 16, from the input and output circuits to the adjustable coupling capacitor 73. At higher frequencies, the 70 anode 41 of the high frequency amplifier tube 38 and

the input terminal 28b b is turned on for the FM Abstimmvorricbtung. 1 In this case, an aperiodic choke 74 is in the line 35b, which runs from the terminal 28 & to the output coupling loop 32 &, in order to prevent the capacitor 34 & from causing the anode 41 to be grounded in the upper frequency range. A crystal rectifier 75 is placed between the output terminal 33 b of the tuning device 1 b and a terminal 76. Aperiodic chokes 77 and 78 are located between the terminals 76 and earth or between the line 35 b and: earth: in order to create a direct current return line for the rectifier 75. A filter capacitor 79 ¹ for high frequency is also located between terminal 76 and earth. The terminal 76 is connected to an output terminal 80 for intermediate frequency by means of a series circuit which has a self-induction. 81 and one. Has capacitor 82.

The receiver 36 is provided with a radio frequency oscillator 83 which may be of any known type, such as that described in connection with FIGS. 6-9. The output energy of the oscillator 83 can be dissipated from the tuning device 1 b by means of a line 84 which is connected to a conductive probe 85 which extends into the housing 2 b of the tuning device through an opening 86.

If the oscillator 83 and the tuning devices 1 a, 1 b and 63 are tuned together between the upper and lower end of the frequency range of the receiver 36, an automatic transition takes place between the antennas 50 and 49 for VHF or decimeter waves.

The tuning devices la and Ib act as cavity resonators in the decimeter range and thus result in an extremely high circular quality. This is very advantageous in the amplifier circuits for high frequency, since it ensures an improved selectivity. In this way, the radio frequency receiver is better able to exclude characters at or near the frame rate.

In Fig. 6, a somewhat modified tuning device 87 is shown, which is also extremely capable of covering a wide frequency range, for example the range from 54 to 890 megahertz.

Around the upper part of their frequency range to detect, the tuning device is provided with an elongated, conductive metallic housing 88, that as a multiple, contiguous cavity resonator for quarter-wave resonance Frequencies in the vicinity of 890 megahertz is effective. The illustrated resonator housing is in cross section rectangular, as can be seen from Fig. 7 and: 8: is, and is end-walled on opposite ends 89 and 90 provided.

In order to produce resonance at relatively low frequencies, a coil 91 is axially inserted Housing 88 arranged. The coil 91 may be made of metal, which is on an insulating tubular Support 92 (Figs. 7 and 8) depressed or otherwise in a generally helical shape Course is formed. A thin layer 93 of low loss dielectric material can be applied to the Coil 91 may be applied in order to isolate and protect the coil, the layer being so thin that it is translucent. The one end section 94 of the coil 91 is in this case with a contiguous cylindrical metallic extension 95 connected to the core 92 coaxially to Coil is helped.

The tuning device 87 is tuned by means of an elongated tuning member 96 which is so is arranged that a relative movement between the tuning member and the housing 88 take place can. If the tuning member 96 can also take various forms, it is an elongated sleeve shown, which can be telescopically pushed over the spool 91 into the cylindrical extension.

The tuning sleeve 96 shown is in the left one

ίο end section 97 narrowed on the inside, so that it is with fairly a tight sliding fit on the spool 91. Although the sleeve 96 can in some cases in the immediate conductive contact with the coil 91, but it is preferable to isolate the coil from the sleeve in order to to make a capacitive exchange of energy between these parts. In this case the insulating coating 93 the desired insulation.

For the upper portion of the tuning range of the tuner 87 a variable capacitance between the tuning sleeve 96 and the resonator 88 by means of a coupling member is provided in the form of a ring 98 which is mounted in alignment with an axial opening 99th The sleeve 96 has at its extreme right end an enlarged end portion 100 which forms a fairly close sliding fit with the energy transfer member: 98. An insulation 101 is provided between the sleeve 96 and the ring 98, which enables a capacitive transfer of energy between the ring 98 and the sleeve 96 when the sleeve is moved to the left around the enlarged end section 100 in alignment with the ring 98 bring to. The ring 98 thus serves to couple the sleeve 96 to the end wall 90 ^{1 of} the cavity at the upper end of the tuning range of the tuning device 87.

In order to provide an energy transfer to the tuning sleeve 96, in this embodiment a second energy transfer member 102 next to the sleeve 96 at a distance from, the coupling ring 98 arranged. In this case, the energy transfer member 102 takes the form of an elongated coupling ring or a coupling sleeve, which is in the Housing 88 is held by means of an insulating piece 103. Over the range of relative movement between of the sleeve 96 and the housing 88, at least a part of the sleeve is always located in the energy transfer member 102 and is therefore capacitive with it coupled to the ring.

Provision is made for energy transfer to and from one end of coil 91. During it in some cases it may be possible to connect a lead directly to the coil 91 is preferred a capacitive energy transfer member 104 uses which take various forms can, but is shown as a conductive metallic ring, which extends from the end portion 94 of the coil, metallic cylinder 95 surrounds. The coating 93 on the spool provides insulation between the Cylinder 95 and the ring 104. In addition, an air gap 105 is provided between these parts.

An exchange of energy between the coupling ring 104 and to provide the resonator housing 88, capacitive coupling members 106 are with the Ring 104 connected. In the present case the links 106 are in the form of flanges or plates, attached to the ring and closely spaced from the end wall 89. A sheet or Film 107 of a low-loss, dielectric material, for example mica, is preferably inserted between the plates 106 and the end wall 89. the end

Claims (6)

9 10 Screws 108 made of an insulating material serve the tuning device 87 as well as the coil 91, the in addition, the plates 106 on the end wall 89 to sleeve 96 and the rings 102 and 104 a resonance, and the distance between the plates and the capacitance between the ring 104 and the device of the bulkhead. This way you can; the housing 88 serves to maintain the relationship between the capacitive coupling between the ring 104 and the 5 voltages of the high frequency anode and the grid Housing 88 of the cavity can be adjusted. to regulate. The sleeve 96 can be moved along the spool 91 by means of a cam when the sleeve is in the dashed line in FIG. 6 109 are moved, which is moved on a rotatable position, the entire coil 91 is active control shaft 110 is attached. A flexible insulating seal is inserted between rings 102 and 104, Rod 111 connects the sleeve 96 with a pivot pin io Thus this position represents that of the lower frequency 112, the corresponding end of the tuning range of Abist attached to a cam follower arm 113, which carries a roller 114, which is represented by a tuning device 87. Tension spring 115 against the cam 109 is pressed. When the sleeve 96 is moved to the left into the position shown in FIG. 6, section 100 of the sleeve 96 will be attached. A longitudinal 15 tuning device for the upper frequency slot 117 can be formed in the guide tube 116 corresponding end of its tuning range in order to allow the arm 113 to pass through. represents. In this position, the entire coil 91 and while the tuning device 87 are surrounded by many instructions - a part of the cylinder 95 at one end of fertilizer in various types of circuits of the sleeve 96. The coil 91 can thus be learned that it is particularly well made for use 20 ineffective or switched off. The sleeve 96 is suitable for circuits that require a tuning device to be located for the most part in the resonator with two ungrounded terminals, between housing 88, but extends partially in those where the tuning device has a resonant circuit ring 98. In this position, the sleeve 96 has . These two ungrounded terminals will housing the resonance of a multiple VDIi ring 102 and 104 formed. 25 hanging \ ^r iertelwellenlängenhohlraums shown by in FIG. 6, the Abstimmvorrich- is the effective capacitance between the end walls tung switched into an oscillator circuit 118 87 is loaded 89 and 90, which is composed of the in the frequency converting part, a radio - The capacities between the ring 98 and the sleeve receiver »for example, can be used. 96, between the sleeve 96 and the cylinder 95, the oscillator 118 contains an electron tube in 30 between the cylinder 95 and the ring 104 and form a triode 119, which has a cathode 1.20, one between the ring 104 and the end wall 89, the cathode heater 121, an anode 122 and a grid are all connected in series. The sleeve 96 and 123 has. Wide strip conductors 124 and 125 of the cylinder 95 can together form an axial mandrel that serves to connect the anode 122 and the grid 123 to the cavity resonator 88 between the rings 104 and 102. The operating 35 end walls 89 and 90 extends. High-frequency voltage is supplied to the anode 122 by means of an interface between the rings 102 and 104 because of the odic choke 126 and the resistors 127 and their spacing along the axis of the rescwiator 128, which is in series between the anode and housing 88. a connection terminal 129 for the positive anode When the sleeve 96 is moved out of the line potential is switched on. A shunt condenser 40 dotted position in Fig. 6 to the right becomes the Sator 130 can be moved further into the ring 98 between the terminal 129 and the earth sleeve, whereby be laid. The energy can flow from the anode 122 to the capacitance between the ring and the sleeve an output terminal 131 can be enlarged by means of a coupling. By moving the sleeve capacitor 132 are transmitted. A resistor 96 exposes the left end section 94 of the coil 91 133 for the pre-tensioning of the grid connects im presented 45 and. the expanded portion 100 of the sleeve lying case the grid 123 with earth. the ring 98 moved out. Accordingly finds In order for the cathode 120 to be independent of the earth, a gradual transition from cavity resonance to potential, it is held by an aperiodic coil resonance. Choke 134 connected to ground. In the same way, the sleeve 96 acts as a heavy load on the is an aperiodic choke 135 in series with the 50 enclosed by the sleeve portion of the coil. To the- Cathode heater 121. accordingly, the sleeve largely prevents this If the sleeve in Fig. 6 full occurrence of disruptive secondary resonances in the Assumes position, the tuning device 87 is ineffective part of the coil 91. at an intermediate point in their frequency range It is obvious that the figure of merit or the Voted. The expanded section 100 of the sleeve 55 circular quality of the tuning devices according to the invention is pulled out of the ring 98, with the earth on the whole tuning range on one result that the impedance between the sleeve 96 and high value is kept. This is largely due to the housing 88 is small. The in the sleeve 96 is due to the fact that the tuning mechanism sensitive part of the coil 91 is capacitive with the sleeve pointing in the section of the high coupled, and the sleeve is in turn capacitive with 60 frequencies of the tuning range as a cavity the ring 102 used for energy transmission behave resonators, couples. At the other end of the spool is the cylinder
capacitively coupled to ring 104. So is the patent claims located between the ring 104 and the sleeve 96: Lent part of the coil effectively between the anode 122 65 and the grid 123 of the oscillator tube 119. Wide range tuning device with a switches. Apparently, the inductance of the coil is adjustable relative to a self-induction element. together with the capacitance between the anode, the capacitive tuning element whose adjustment and the grating 123 together with the shifting a change in the effective self-induction which distributed capacitances between these lines 70 of the self-induction element caused thereby characterized in that the tuning member and the self-induction coil, preferably concentrically, are arranged in a housing, for a (high-frequency.) part of the movement path of the tuning member the same, with the housing forms a cavity resonator, while for the other (lower frequency) part of the trajectory the tuning primarily by changing the effective inductance of the coil takes place. 2. Apparatus according to claim 1, characterized in that a mandrel (5, 95) made of conductive Fabric axially on one. End wall of the housing is attached and the coil (6, 91) in axial Extension of the dome is such that the tuning member is in the form of an elongated conductive sleeve (!. (λ, 96), which the coil and the mandrel arbitrarily able to enclose far that the other end wall of the housing has an opening for has the passage of the sleeve and that a ring (12, 98) for the capacitive coupling to this end wall is mounted in alignment with the opening. 3. Apparatus according to claim 2, characterized in that an energy transfer member (16, 102) is mounted in alignment with the coupling ring in the axial direction. 4. Apparatus according to claim 2 or 3, characterized in that the remote from the coil End of the sleeve (10, 96) has a larger outer diameter than that of the coil adjacent Has the end. 5. Device according to one or more of claims 1 to 4, characterized in that an input loop and an output loop are provided in the cavity resonator. 6. Device according to one or more of claims 1 to 5, characterized in that one end of the coil is capacitively coupled to an end wall of the housing. Considered publications:
German patent application L 5082 VIIIa / 21a ⁴ ;
U.S. Patent No. 2,645,718;
British Patent No. 554 SSO-French Patent No. 1 049 282. 1 sheet of drawings © 709 910/296 3.58