EP0345482A1 - Coaxial-antenna selector - Google Patents

Abstract

In the case of a coaxial antenna selector with a plurality of input lines (21a, b) and a plurality of output lines (24a, b), a reduction in the switching and control effort and in the crosstalk sensitivity is achieved in that each of the lines (21a, b; 24a, b) a coaxial, movable connecting element (22a, b; 23a, b) is assigned, which allows a direct connection between any transmitter (TX1,2) and any antenna (A1,2).

In the simplest case, the connecting elements (22a, b; 23a, b) are designed as telescopically extendable extensions of the input and output lines (21a, b; 24a, b).

Description

Technical field

The present invention relates to the field of transmission technology. It relates in particular to a coaxial antenna selector
- A plurality of coaxial input lines for feeding RF power to corresponding transmitters;
- a plurality of coaxial output lines for delivering the RF power to corresponding antennas; in which
- Each input line can optionally be connected to each output line.

Such an antenna selector is e.g. known from EP-B1 0 044 099.

State of the art

In large radio broadcasting systems, particularly in the shortwave range, a plurality of independently operating individual transmitters are used which, depending on the time of day and the program, radiate the amplitude-modulated carrier signal via different antennas.

The RF power, which is usually in the range of several 100 kW, is fed from the respective transmitter into the respective antenna via heavy-duty coaxial lines (50 ohms).

In order to enable a fast and flexible connection establishment between the individual transmitters and antennas, a coaxial antenna selector is arranged between the two, with the help of which any desired connection between any transmitter and any antenna can be switched in a short time.

Known coaxial antenna selectors are constructed according to the matrix principle (EP-B1 0 044 099). With these matrix selectors, the input lines coming from the transmitters form the rows and the output lines going out to the antennas form the columns of a matrix.

Coaxial changeover switches are arranged in pairs in the nodes of the matrix, which connect the respective row or column line in one switching position, and in the other switching position disconnect both lines and connect in the node via a corner.

On the one hand, this means that with n transmitters and m antennas, i.e. with an (n x m) matrix, 2 nm switches are required, all of which require their own drive and control.

On the other hand, when switching over corners in the antenna selector of the conventional type, lines with open ends remain, in which high voltages can be induced during operation, which can lead to faults in the system if additional countermeasures are not taken (so-called crosstalk).

Finally, the large number of switches that are in a switched connection leads to a corresponding one large number of contact points in the line connection, which are naturally weak points.

Presentation of the invention

It is therefore an object of the present invention to provide a coaxial antenna selector which is distinguished by a significantly lower amount of circuitry and control, has fewer contact points and a lower sensitivity to crosstalk.

With a coaxial antenna selector of the type mentioned at the outset, the object is achieved in that
- Each input line and each output line is assigned a single, movable connecting element in the form of a coaxial line; what coaxial line
- With one line end to the associated input or. Output line is connected; and
- With the other, open line end is displaceable along an associated displacement line; such that
- Each displacement line of a connecting element assigned to an input line intersects all displacement lines of the connecting elements assigned to the output lines.

The essence of the invention is therefore to connect the associated input and output lines in the antenna selector directly to one another with the aid of a movable line section for each connection that is switched through between a transmitter and an antenna. There are therefore no longer any switches assigned to the matrix node, but only those assigned to the respective input and output lines (ie only (n + m)) movable connecting elements that have to be driven and controlled. The number of crosstalk-sensitive line sections within the antenna selector is accordingly reduced accordingly.

According to a first preferred exemplary embodiment of the invention, all the displacement lines are straight lines, the displacement lines of the connecting elements assigned to the input lines run parallel to one another and perpendicular to the displacement lines of the connecting elements assigned to the output lines, and the connecting elements are each designed as telescopically extendable extensions of the input or output lines ( Fig. 4).

This type of antenna selector can be implemented particularly easily because only linear displacements occur here, and therefore neither swivel nor ball joints are required.

Further exemplary embodiments result from the subclaims.

Brief description of the drawing

• Fig. 1 eine Antennenwähler-Matrix mit paarweisen Umschaltern nach dem Stand der Technik;
• Fig. 2 den Aufbau eines Umschalters aus Fig. 1;
• Fig. 3 das Prinzipschema des direkten Verbindungsaufbaus bei einem Antennenwähler nach der Erfindung;
• Fig. 4 ein erstes Ausführungsbeispiel eines koaxialen Anten­nenwählers nach der Erfindung mit teleskopartig aus­ziehbaren Verbindungselementen;
• Fig. 5 ein zweites Ausführungsbeispiel analog zu Fig. 4 mit Verbindungselementen, die aus mehreren, über Drehge­lenke verbundenen Leitungselementen bestehen;
• Fig. 6 ein drittes Ausführungsbeispiel, bei dem die Verbin­dungselemente teilweise linear verschiebbar und teil­weise drehbar ausgeführt sind;
• Fig. 7,8 weitere den Fig. 5 und 6 entsprechende Ausführungs­beispiele, bei denen anstelle der Drehgelenke Kugel­gelenke eingesetzt werden;
• Fig. 9 ein Ausführungsbeispiel für ein solches Kugelgelenk; und
• Fig. 10 ein Ausführungsbeispiel für ein Drehgelenk aus Fig. 5 und 6.

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the drawing. Show it:

• Figure 1 shows an antenna selector matrix with paired switches according to the prior art.
• Fig. 2 shows the structure of a switch from Fig. 1;
• 3 shows the basic diagram of the direct connection establishment in an antenna selector according to the invention;
• Figure 4 shows a first embodiment of a coaxial antenna selector according to the invention with telescopically extendable connecting elements.
• FIG. 5 shows a second exemplary embodiment analogous to FIG. 4 with connecting elements which consist of several line elements connected via swivel joints;
• Fig. 6 shows a third embodiment in which the connecting elements are partially linearly displaceable and partially rotatable;
• 7,8 further exemplary embodiments corresponding to FIGS. 5 and 6, in which ball joints are used instead of the rotary joints;
• 9 shows an exemplary embodiment of such a ball joint; and
• 10 shows an exemplary embodiment for a swivel joint from FIGS. 5 and 6.

Ways of Carrying Out the Invention

The scheme of a conventional coaxial antenna selector for a (2 x 3) matrix is shown in FIG. 1. The antenna selector has two inputs for connecting two transmitters TX1 and TX2, and three outputs for connecting three antennas A1, A2 and A3.

Accordingly, there are two coaxial input lines (rows of the matrix) and three coaxial output lines (columns of the matrix), which intersect at six nodes.

Pairs of changeover switches are provided in each of these intersection points, four of which (1, .., 4) are highlighted by a dashed outline.

Within such a pair of changeover switches (2, 3), one changeover switch (2) is inserted into the associated input line.

The changeover switches 1, .., 4 each have two switching positions: in one switching position (in FIG. 1 for the changeover switches 1 and 4), the coaxial lines into which the changeover switches are inserted are connected through.

In the other switching position (in the case of the changeover switches 2 and 3), the coaxial lines are separated and connected at the intersection by means of an additional conductor strand 5 via a corner. In the example of FIG. 1, the antenna A2 is connected to the transmitter TX2 in this way.

As you can easily see, this low-dimensional (2 x 3) matrix already requires 12 changeover switches, all of which have to be driven and controlled by a motor.

Furthermore, the exemplary switching connection between transmitter TX2 and antenna A2 in FIG. 1 contains at least eight contact points (two contact points per switch), which are susceptible to high mechanical and electrical loads, due to the changeover switches 1,... 4 used in this connection Form weak points in the connection.

Finally, in the known antenna selector there always remain conductor pieces with open ends, which promote crosstalk and thus disrupt the operation.

The internal structure of a known switch is shown in Fig. 2. The changeover switch naturally has a coaxial structure, ie it includes both inner conductors in the direction of the line 9,17 and outer conductor 18, as well as in the branching inner conductor 7 and outer conductor strand 6.

For switching, a connecting element 13 is provided in the inner region of the line, which consists of an outer tube 12 and an inner tube 15.

The outer tube 12 is pivotally attached at one end to a joint ball 10 which sits at the end of an inner conductor 9. The inner tube 15 is telescopically displaceable in the outer tube 12. Outer tube 12 and joint ball 10 as well as inner tube 15 and outer tube 12 are each electrically connected to one another by a tulip contact 11 and 14.

Additional tulip contacts 8 and 16 are attached to the ends of the inner conductors 7 and 17 and establish the connection to the inner tube 15 in the respective switching position.

The actual technical implementation of such a switch and a matrix realized with the switch can be found in the rest of publication no. CH-E 3.10559.2 E from BBC Brown Boveri AG, Baden (Switzerland).

While in the conventional antenna selector the switched connection runs over a large number of individual switches, the respective input and output lines are connected directly in the antenna selector according to the invention, as is shown in the example of a (4 × 5) matrix in FIG. 3. The switched connections TX1 transmitter - Antenna A3 TX2 transmitter - antenna A2 TX4 transmitter - A4 antenna are marked here by the solid lines. The dashed lines only show other possible routes without any cables actually running there in this switching state.

Different embodiments of the invention, which are based on a matrix arrangement, are shown in FIGS. 4, 5 and 7.

In these embodiments, a plurality of coaxial input lines 21a, b and output lines 24a, b are fixedly arranged in a frame structure 19. The input lines 21a, b run parallel to one another and perpendicular to the likewise parallel output lines 24a, b.

Each input and output line 21a, b or 24a, b is assigned a single, movable connecting element 22a, b or 23a, b. The connecting elements 22a, b and 23a, b likewise have the form of a coaxial line and are connected with the one line end to the associated input or output line 20a, b or 24a, b.

The other, open line end of the connecting elements 22a, b or 23a, b can be displaced along an associated displacement line V1, .., V4 (FIG. 4).

All displacement lines V1, .., V4 lie in one plane. The displacement lines V1.2 of the connecting elements 22a, b assigned to the input lines 21a, b run parallel to one another and perpendicular to the parallel displacement lines V3.4 of the connecting elements 23a, b assigned to the output lines 24a, b.

If, for example, the antenna A2 is now to be connected to the transmitter TX2, the connecting elements 22b and 23b of the input line 21b and output line 24b are shifted along their displacement line V2 or V4 to the intersection of these lines.

Since the open ends of the connecting elements 22b and 23b are designed such that they are directly opposite one another in this position, a continuous coaxial connection is made in this way from the transmitter TX2 to the antenna A2.

Other connections between a transmitter and an antenna can be switched if the corresponding connection elements are brought into contact with the open line ends at the corresponding other intersection points of their displacement lines.

The movable connecting elements 22a, b and 23a, b can be realized in different ways. 4, the connecting elements 22a, b and 23a, b are designed as telescopically extendable extensions of the input and output lines 22a, b and 24a, b, respectively.

The extensions are bent several times at right angles at the open ends, so that the displacement lines V1, ..., V4 run in a plane which lies between the planes of the input lines 21a, b and output lines 24a, b. In this way, all possible connections between the transmitters TX1.2 and the antennas A1.2 can be switched freely.

For the connection of the transmitters TX1, 2, the input lines 21a, b in this example have flange-like transmitter connections 20a, b. Antennas A1, 2 are connected via corresponding antenna connections 25a, b to output lines 24a, b.

Furthermore, it is possible, as shown in FIGS. 4, 5 and 7, to provide additional output lines 97a, b which are opposite to the input lines 21a, b and can likewise be connected to the input lines 21a, b via the connecting elements 22a, b. These additional output lines 97a, b can be used, for example, for further antennas or as line terminations.

As an alternative to the design of the connecting elements 22a, b and 23a, b as extendable extensions according to FIG. 4, as shown in the exemplary embodiment in FIG. 5, the connecting elements can each consist of at least two successive line elements 27a, 29a or 27a, 29b or 32a , 34b or 32a, 34b, which are connected to each other via a first swivel joint 28a, b; 33a, b and via a second swivel joint 26a, b; 35a, b to the associated input or output line 21a, b or 24a, b are connected.

The axes of rotation of all rotary joints 26a, b; 28a, b; 33a, b; 35a, b are each perpendicular to the central axis of the associated input and output lines 21a, b and 24a, b.

Due to the two vertical swivel joints per connecting element, the same displacement lines are realized for the open line ends as in the example in FIG. 4.

In order to facilitate the adjustment of the open line ends when interconnecting because of the kinking movement of the connecting elements 22a, b and 23a, b, in the arrangement according to FIG a further swivel joint 30a, b is provided (both can equally well be arranged on the connection elements 23a, b on the output side).

Another alternative is shown in FIG. 7. Here ball joints 44a, 46a, 48a; 44b, 46b, 48b; 53a, 55a, 57a; 53b, 55b, 57b are used in the connecting elements 22a, b and 23a, b the at least three successive line elements 45a, 47a, 49a; 45b, 47b, 49b; 52a, 54a, 56a; Connect 52b, 54b, 56b per connecting element and connect to the associated input or output line 21a, b or 24a, b.

An additional line element and ball joint per connecting element compared to FIG. 5 is provided in this case because the coaxial ball joints only allow a limited angle of rotation.

The line elements 31a, b and the rotary joints 30a, b in FIG. 5 correspond in the exemplary embodiment of FIG. 7 to the line elements 51a, b and the ball joints 50a, b, which enable better adaptation of the open line ends when interconnected.

While in the previous exemplary embodiments of FIGS. 4, 5 and 7, straight lines intersecting each other as displacement lines V1, .., V4 were used which lay in a common plane, the exemplary embodiments shown in FIGS. 6 and 8 have straight lines and circles as displacement lines on, which run in a common cylindrical surface 37.

Here, too, the input lines 21a, b are arranged in parallel one above the other and end in the cylinder axis 36 of the cylinder jacket surface 37.

The connection elements 22a, b on the input side each comprise at least one line element which is connected to the associated input line 21a, b via a first swivel joint 38a, b lying in the cylinder axis 36 (FIG. 6).

Since the axes of rotation of the rotary joints 38a, b are perpendicular to the central axes of the input line 21a, b and coincide with the cylinder axis 36, the corresponding displacement lines V1.2 form parallel circles in the cylinder jacket surface 37.

The output-side connecting elements 23a, b in turn each comprise at least two successive line elements 40a, 42a or 40b, 42b, which are connected to one another via a second swivel joint 43a, b to the associated output line 24a, b are closed. With this configuration, which is analogous to FIG. 5, the corresponding displacement lines V3.4 are straight lines, which run parallel to the cylinder axis 36 in the cylinder jacket surface 37 and intersect the circular displacement lines V1.2 perpendicularly.

Additional line elements 39a, b and swivel joints 96a, b also ensure an improved adaptation of the line ends here.

The transition from the embodiment of FIG. 6 to the embodiment of FIG. 8 is the same as the transition from FIG. 5 to FIG. 7: In this case too, the rotary joints are replaced by ball joints 58a, b; 60a, b; 62a, b; 64a , b and 66a, b replaced. The output-side connecting elements 23a, b then comprise the line elements 59a, b; 61a, b; 63a, b and 65a, b with an additional line element per connecting element for the reasons already mentioned above.

In the case of the connecting elements 22a, b on the input side, an additional line element can be dispensed with, since in this case the limited pivoting range of the ball joints 58a, b is sufficient.

The embodiments with a swivel joint (parallelepiped according to FIG. 5 and cylinders according to FIG. 6) have the advantage over the embodiment with a telescopic mechanism (FIG. 4) that no line pieces sliding into one another have to be used. In addition, with the construction volume of the antenna selector remaining approximately the same, the operating area, i.e. the area in which the displacements take place is reduced.

The construction volume and operating area are particularly small in the embodiments with a ball joint (FIGS. 7, 8).

Although only one (2 × 2) matrix has been considered in the exemplary embodiments, it goes without saying that the principles shown can be easily applied to larger matrices.

The advantages over the previously known coaxial antenna selector are:
- Savings in drives and control elements;
- very few contact points;
- no open line sections, therefore no mutual coupling (crosstalk);
- easy control; and
- easy maintenance.

5 to 8, ball joints and rotary joints are used for the flexible connecting elements 22a, b and 23a, b.

Examples of such ball and swivel joints are shown in FIGS. 9 and 10.

9 is constructed coaxially and comprises two inner conductors 67, 76, which merge into two inner spherical shells 72, 73 in the interior of the joint. The two spherical shells 72, 73 lie one inside the other and form a joint with ball and socket that can be rotated on all sides. A secure electrical connection between the spherical shells 72, 73 is achieved by a contact spring 75 arranged between them.

Flanges 69, 77 are provided for the outer conductor on both sides of the joint, which pass into corresponding spherical shells 70, 74 with a corresponding contact spring 71. The inner conductors 67, 67 are supported on the flanges 69, 77 by insulating rings 68, 78.

10 shows two variants of a suitable swivel joint. Both variants include two inner conductors 81, 85 and two off senleiter 80,94, which abut each other in the joint and are conductively connected at this point by contact springs 83,87.

The outer conductors 80.94 also merge into flanges 79.95 at the ends of the joint and also carry insulating rings 82.84 on the inside, which fix the inner conductors 81.85.

At the connection point between the two outer conductors 80, 94, one outer conductor 94 engages over the flange-like end of the other outer conductor.

In one variant (to the left of the dash-dotted center line), two ball bearings 91, 92 are inserted in this part of the joint, which rotatably support one outer conductor 80 in the other outer conductor 94.

In the other variant (to the right of the center line), this task is performed by a guide ring 88 which encompasses the flange-like end of the outer conductor 80.

In both variants, the rotary connection is secured by a coupling ring 93, 89, which holds the ball bearings 91, 92 or the guide ring 88 in their position and is held by fixing screws 90. A spring carrier 86 is also provided for the contact spring 87 of the outer conductor 80, 94 and holds the spring in position between the insulating rings 82, 84.

Claims (8)

1. Coaxial antenna selector with a) a plurality of coaxial input lines (21a, b) for feeding in RF power corresponding transmitters (TX1, .., TX4); b) a plurality of coaxial output lines (24a, b) for delivering the RF power to corresponding antennas (A1, .., A5); in which c) each input line (21a, b) can optionally be connected to each output line (24a, b);
characterized in that d) each input line (21a, b) and each output line (24, ab) is assigned a single, movable connecting element (22a, b or 23a, b) in the form of a coaxial line; what coaxial line e) one end of the line is connected to the associated input or output line (21a, b or 24a, b); and f) can be moved with the other, open line end along an associated displacement line (V1, .. V4); such that g) each displacement line (V1,2) of a connecting element (22a, b) assigned to an input line (21a, b) intersects all displacement lines (V3,4) of the connecting elements (23a, b) assigned to the output lines (24a, b). 2. Antenna selector according to claim 1, characterized in that a) all displacement lines (V1, .., V4) are straight lines; and b) the displacement lines (V1,2) of the connecting elements (22a, b) assigned to the input lines (21a, b) parallel to each other and perpendicular to the displacement lines (V3,4) of the connecting elements (23a, b) assigned to the output lines (24a, b) ) run. 3. Antenna selector according to claim 2, characterized in that the connecting elements (22a, b; 23a, b) are each designed as telescopically extendable extensions of the input or output line (21a, b or 24a, b) (Fig. 4) . 4. Antenna selector according to claim 2, characterized in that a) the connecting elements (22a, b; 23a, b) each comprise at least two successive line elements (27a, 29a; 27b, 29b; 32a, 34a; 32b, 34b); b) the line elements of a connecting element are each connected to one another via a first swivel joint (28a, b; 33a, b); c) a line element (27a, b; 34a, b) of each connecting element (22a, b; 23a, b) via a second swivel joint (26a, b; 35a, b) to the associated input or output line (21a, b or 24a, b) is connected; and d) the axes of rotation of both rotary joints (25a, b; 28a, b; 33a, b; 35a, b) each perpendicular to the central axis of the audible input or output line (21a, b or 24a, b) are available (Fig. 5). 5. Antenna selector according to claim 2, characterized in that a) the connecting elements (22a, b; 24a, b) each comprise at least three successive line elements (45a, 47a, 49a; 45b, 47b, 49b; 52a, 54a, 56a; 52b; 54b, 56b); b) the line elements of a connecting element are each connected to one another via two ball joints (46a, 48a; 46b, 48b; 53a, 55a; 53b, 55n); and c) a line element (45a, b; 56a, b) of each connecting element (33a, b; 23a, b) via a third ball joint (44a, b; 57a, b) to the associated input or output line (21a, b or 24a, b) is connected (Fig. 7). 6. Antenna selector according to claim 1, characterized in that a) all displacement lines (V1, .., V4) are lines on a common cylinder surface (37); in which b) the displacement lines (V1,2) of the connecting elements (22a, b) assigned to the input lines (21a, b) are circles and the displacement lines V3,4) of the connecting elements (23a, b) assigned to the output lines (24a, b) are straight lines; or the other way around. 7. Antenna selector according to claim 6, characterized in that a) the connecting elements, the lines of displacement of which are circles, each comprise at least one line element which is connected to the via a first swivel joint (38a, b) orderly input or output line (21a, b; 24a, b) is connected; b) the connecting elements, the lines of displacement of which are straight, each comprise at least two successive line elements (40a, 42a; 40b, 42b) which are connected to one another via a second swivel joint (41a, b) and to the via a third swivel joint (43a, b) assigned output or input line (24a, b or 21a, b) are connected; and c) the axes of rotation of the rotary joints (38a, b; 41a, b; 43a, b) are each perpendicular to the central axis of the associated input or output line (21a, b or 24a, b) (FIG. 6). 8. Antenna selector according to claim 6, characterized in that a) the connecting elements, whose displacement lines are circles, each comprise at least one line element which is connected via a first ball joint (58a, b) to the assigned input or output line (21a, b or 24a, b); and b) the connecting elements, the lines of displacement of which are straight, each comprise at least three line elements (61a, 63a, 65a; 61b, 63b, 65b) which are connected to one another via two further ball joints (62a, 64a; 62b, 64b) and via a further ball joint (66a, b) are connected to the assigned output or input line (24a, b or 21a, b) (Fig. 8).

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