MXPA99010397A - Filter tuning device and tuning plate including a number of such devices - Google Patents

Abstract

The present invention relates to a tuning device in a radio filter equipment for mobile telephony in which one or more cavities in the equipment should be tuned to the right frequency. The invention also relates to a tuning plate including a number of such tuning devices. The tuning device (401) consists of preferably regular or square formed depressed parts (1, 6) in the tuning plate (300) of the filter equipment. The depressed part converges each to a square formed central plate (5) which is provided with an elevation or bulb (3) upwards. By turning a tuning screw on the equipment will then develop a force on the plate and the surrounding depressed parts. This implies that the tuning can be made automatically, more secure and with less risk for intermodulation. Different embodiments of the depressed parts are described.

Description

FILTER TUNING DEVICE AND TUNING PLATE INCLUDING SEVERAL DEVICES OF THIS TYPE TECHNICAL FIELD OF THE INVENTION The present invention generally relates to radio filters, for example bandpass filters that can be found in the HF area, employed, for example, in a mobile radio system, and more particularly to tune such filters. Descron of the Related Art A certain type of tuning arrangement is required to tune an HF filter to the correct frequency. This can be done, for example, with a tuning screw alone or with a tuning plate where a tuning screw displaces a part of the tuning plate. A conventional BP (bandpass) filter includes a body, a cover, filter cavities, center conductors, tuning screws, an input loop, an output loop and connectors. The walls of the filter cavities are formed by the internal surfaces of a filter frame. The filter frame is formed of the hollow body and the lid. The center conductors are placed inside the filter cavities. Tuning screws to tune the filter, ie the center conductors, at the correct frequency, are arranged in the cover and extend into the filter cavities. A tuning screw is arranged in the lid for the center conductor in the filter. Each of the center conductors is provided for receiving and / or transmitting radio signals within different frequencies. The input loop and the output loop are connected to connectors and the connectors are connected with cables to functional units such as printed circuits (PCBs) and antennas. The arrangement of the various elements in a filter in accordance with that described above is well known in the art. In a typical state of the art systems, tuning screws are used with locknuts. The filter is tuned by turning the screw until the correct frequency is set for the corresponding center conductor. When this has been done, the screw is fixed by tightening a lock nut on the screw. When the screw is rotated, the capacitance between the screw and the center conductor changes. The tuning of a filter with a tuning plate is carried out "in the same way, by rotating a tuning screw." The difference is that instead of using a lock nut to fix the tuning screw in position A tuning plate can be used, the screw displaces a part of the tuning plate axially when the screw is turned in. This creates a tension in the tuning plate which increases the friction for the tuning screw when it rotates and consequently fixes the In this case, the capacitance changes by the movement of a part of the tuning plate, the screw moves only the plate and does not have a major impact on the capacitance change. the current technique has curved indentations formed in a rose pattern around each area of the tuning plate that corresponds e to a tuning screw. The shape of the slits allows the central part of the rose to move axially. COMPENDIUM OF THE INVENTION The present invention focuses on the timing plate placed between the body and the lid. It can be seen that the current approach presents problems. First, the tuning of the first type of state of the filters of a technique that are tuned without using a tuning plate creates a problem when a test is performed because two tools are required when tightening the lock nut. If a tuning screw with a lock nut is used, the rotation of the lock nut will also cause the screw to rotate. Therefore, a second tool must be used to hold the screw while using a first tool to tighten the lock nut. This method is problematic because it requires more time, more space, and the use of more tools than is necessary or optimal. Second, when using a tuning plate of the current technique with curved grooves in the form of a rose, the resistance to grounding is relatively high and currents do not take the shortest route to the earth. To avoid intermodulation, IM, some of the tuning screws must be electrically isolated from the tuning plate, preferably with PTFE gaskets.

(Teflon) that are fixed on the tuning plate. Normally, the parts in a filter are manufactured with high precision in the surfaces that form the contact surfaces between the tuning plate and the body, and the connection is made through the use of screws. To minimize electromagnetic radiation (EMC), the electrical contact between the cast part, that is, the body, and the tuning plate must be excellent. To meet the requirements of the high working frequencies (around 1.8 Ghz) for the filters, the distance between the screws must be relatively small (approximately 20 mm) which means that the number of screws required in a filter is significant. Another factor that also emphasizes the need for good contact between the body and the lid is the risk of intermodulation (IM). Holes in the timing plate should be made with a minimum total area to minimize the risk of intermodulation. Accordingly, an object of the present invention is to minimize the problems of having slits in the tuning plate by minimizing the area of the slits. Another object of the present invention is to minimize the problem of currents that do not take the shortest route to the earth by using straight slits instead of the curved slots used in the tuning plate of the current art. Another object of the present invention is the use of spring elements integrated in the synchronization plate to obtain good contact between the body and the tuning plate and in this way minimize the risk of intermodulation (IM). To minimize electromagnetic radiation (EMC), the electrical contact between the body and the tuning plate is excellent due to the springs in the tuning plate. The central idea of the invention is to make a tuning plate with tuning units with straight and narrow slits that diagonally from a center frame and having several depressions in the tuning plate in each tuning unit in such a way that the This tuning plate is in wave form around the center box in order to minimize resistance to grounding, improve the intermodulation characteristics and allow sufficient movement of the plate in the axial direction of a tuning screw. Sufficient movement in this case means at least 2-3mm. It is the combination of clefts and depressions that makes a functional and helpful solution possible. The result will be a filter that can be tuned automatically, which is more effective from a cost perspective and has a lower risk of intermodulation. If the timing plate with the tuning units and springs is designed in accordance with the preferred embodiment of the present invention, the number of fixing screws in the cover can be reduced by approximately 60% compared to the state of the solution current . The function of tuning and electric seal is united in one, that is to say the tuning plate. When the solution is used with recesses and four slits, the area of the tuning plate cooperating with the center conductor is increased by 50% compared to the current state of the art system. The filter is easier to tune if the area is larger (C = epsilon * A / d). The force required to tune the filter is less by a factor of approximately 2-4 due to the easier movement of the tuning unit compared to the rose-shaped state which means that the thickness of the tuning plate can be lower . The area of the holes in the tuning plate can be decreased by approximately half the area required today by the use of straight and narrow slits that meet diagonally from the center square. PTFE (Teflon) electrically insulating gaskets are not required on the tuning plate to isolate some of the tuning screws of the tuning plate due to the smaller area of the slots in the tuning plate ~ and because of the better contact between the body and tuning plate. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described in greater detail with reference to preferred embodiments of the present invention., which are offered by way of example only, and will be illustrated in the accompanying drawings, in which: Figure 1 schematically illustrates a side section view of a filter of the current technique, for example for a mobile telephone system. Figure 2 schematically illustrates a perspective view of a tuning plate of the prior art with screw holes for joining the body, the tuning plate and the lid for a filter, for example in a mobile telephone system. Figure 3 schematically illustrates a side sectional view of a cavity of a filter of the current art, for example, for a mobile telephone system. Figure 4 schematically illustrates a perspective view of the preferred embodiment of the present invention. Figure 5 schematically illustrates a top plan view of the preferred embodiment of the tuning plate where recesses and slits are shown in a tuning unit. Figure 6 schematically illustrates a side cut view of the recesses in a tuning unit of the preferred embodiment of the present invention. Figure 7 schematically illustrates a top plan view of the preferred embodiment of the tuning plate where screws are shown between the tuning units, at the edge of the tuning plate, screw holes for the attachment of the base, cover and tuning plate and also recesses and slots in 10 tuning units. Figure 8 schematically illustrates the preferred embodiment of the spring elements positioned on the edge of the tuning plate of the present invention. Figure 9 (a) schematically illustrates a side view of the preferred embodiment of the spring elements between two tuning units in the tuning plate. Figure 9 (b) schematically illustrates a top view of the preferred embodiment of the spring elements between two tuning units in the tuning plate. Fig. 10 schematically illustrates a side view of a spring at the edge of a tuning plate of the present invention. Figure 11 schematically illustrates a side sectional view showing where the present invention would be located in a filter, for example for a mobile telephone system. Figure 12 schematically illustrates a perspective view of a filter with a tuning plate. DETAILED DESCRIPTION OF THE MODES In summary, the present invention provides an apparatus for tuning radio / BP filters employed, for example, in mobile radio systems. The present invention focuses on the tuning plate 300 placed between the body 111 and the lid 110. Figure 1 schematically illustrates a side sectional view of a filter 20 of the current art, for example, for a mobile telephone system. A conventional BP (bandpass) filter includes a body 111, a cover 110, filter cavities 114, center conductors 112, tuning screws 113, an input loop 120, an output loop 121 and connectors 122, 123. The walls 124 of the filter cavities 114 are formed by the internal surfaces of a filter frame. The filter frame is formed of the hollow body 111 and the lid 110. The center conductors 112 are positioned and within the filter cavities 114. Tuning screws 113 for tuning the filter, i.e. the center conductors 112, a the correct frequency is arranged in the lid 110 and extended in the filter cavities 114. A tuning screw 113 is arranged in the lid 110 for each center conductor 11 in the filter. Each of the center conductors 112 is provided for receiving and / or transmitting radio signals at different frequencies. The input loop 120 and the output loop 121 are connected to the connectors 122, 123 and the connectors 122, 123 may be connected with cables (not shown) to functional units (not shown), such as for example express circuit boards (PCBs) and antennas. The filter is tuned by turning the screw 113 to the correct frequency for the corresponding center conductor 112. When this is done, the screw 113 is fixed by the tightening of a lock nut 115 as can be seen in figure 3 on the screw 113. When the screw 113 is rotated, the capacitance changes between the screw 113 and the corresponding center conductor 112. The tuning of a filter with a tuning plate 100, 300 is done in the same way by rotating a tuning screw 113 to the correct frequency setting. In the filter, the tuning plate is placed between the base and the lid as can be seen in figure 11. The difference is that instead of using a lock nut 115 to fix the tuning screw 113 in position, it can be employing a tuning plate 100, 300, the screw 113 displaces a part of the tuning plate 100, 300 axially when the screw 113 rotates. This creates a tension in the tuning plate, 100, 300 which increases the friction for the tuning screw 113 when it rotates and consequently fixes the tuning screw 113 in position. If more friction is required, a plastic coated screw also known as a retaining screw can also be used. When a tuning plate is used, the capacitance changes by shifting a part of the tuning plate, the tuning unit. In the tuning plate of the current technique 100 illustrated in FIG. 2, the tuning unit 400 is equivalent to the area containing the curved indentations 201 in the form of rose the shape of the slits 201 allows the central part 101 of the rose move axially. The center 102, 302 of the tuning unit in the tuning plate is positioned above the center 142 of the corresponding center conductor. The screw 113 only displaces the plate 100, 300 and does not have a major impact on the change in capacitance. Mechanically adjustable, for example, a tuning screw 113 is provided in combination with a tuning plate, where the tuning screw may or may not be in direct electrical contact with the tuning plate. When a tuning plate 100 of the current art with curved slots 201 is employed in a rose shape, the resistance to the ground connection is relatively high and the currents do not take the shortest route to the ground. To avoid IM intermodulation, some of the tuning screws 113 of the tuning plate must be electrically isolated, preferably with PTFE (Teflon) gaskets which are clamped onto the tuning plate (not shown). Figure 4 schematically illustrates a perspective view of the preferred embodiment of the present invention. The tuning plate 300 has in this mode, 10 tuning units 401. FIG. 5 schematically illustrates a top plan view of the tuning plate 300 where recesses 1, slits 2, and the stop 3 in a tuning unit 401 of conformity to one modality are illustrated. The tuning plate has recesses 1 and slits 2. The recesses 1 are integrated in the tuning plate 300 and formed with different lengths (a, b), as shown in figure 6, which is important for a smooth movement on the plate. The distance (a) must be greater than the distance (b) and the angle between the distance (a) and (b) must be approximately 90 °, preferably greater than 90 ° in order to obtain a smooth movement. At the center of a tuning unit is a raised area, a stop 3 made to absorb the force (F) from the tuning screw. The stop is placed in the middle part of a square 5. The slits 2 extend radially in the tuning plate and beyond the outermost recess 6 as can be seen in figure 5. The tuning plate has a waveform between the slits 2. This means that the recesses 1 are formed with a series of projections 7 and valleys 8 and that these projections 7 and valleys 8 are formed as squares with slits 2 that cut the squares into four substantially identical parts. Other geometric shapes, as for example circles or polygons can also be used. Figure 6 schematically illustrates a side cut view of the recesses about a tuning point of the preferred embodiment of the present invention. Figure 7 schematically illustrates a top plan view of the preferred embodiment of the tuning plate 300 where springs 4 are illustrated at the edges of the tuning plate, springs 11 between the tuning units 401, holes 9 for screws to join the base 111, cover 110 and tuning plate 300 and also recesses 1, slits 2 and stops 3 in 10 tuning units 401. The plate 300 preferably has a thickness of 0.3 mm and is preferably made of plate-coated copper. The tuning plate is protected, that is to say connected to earth, with the help of springs 4,11. The central idea of the invention is to make a tuning plate 300 with tuning units 401 with straight and narrow slits 2 having a diagonal direction from a center square 5 and having several recesses 1 in the tuning plate 300 in each tuning unit in such a way that the tuning plate has a waveform around the center square 5 in order to minimize resistance to grounding, in order to improve the characteristics of IM and to allow sufficient movement of the plate in the axial direction of a tuning screw 113. This combination of the slits 2 and the depressions 1 makes possible a functional and profitable solution. The waveform consists of recesses with two projections 7 and two valleys 8 in the following order: square center plane 5, projection 7, valley 8, projection 7, valley 8, flat surface of the tuning plate 300. The projections 7 they are on the same level as the tuning plate and the valleys 8 are on the same level as the center square 5 as illustrated in figure 6. Figure 8 schematically illustrates the preferred embodiment of the springs 4 placed at the edge of the tuning plate. The springs are integrated into the tuning plate and made by removing material from the tuning plate. A hole 9 for a screw joining the base 111, cover 112, and plate 300 together is also shown. Figure 9 (a) schematically illustrates a top plan view of the preferred embodiment of the springs 11 between two tuning units 401 on the tuning plate 300. These springs 11 are made by removing material from the tuning plate 300. Figure 9 (b) schematically illustrates a side view of the preferred embodiment of the spring elements 11 between two tuning units 401 on the synchronization plate 300. The figure shows how these springs 11 are bent to make better contact with the base by the contact at a point 12. Figure 10 schematically illustrates a side view of a spring at the edge of the tuning plate 300. The tuning plate is connected to ground in the filter wall. The spring 4 is an elongated member integrated in a tuning plate 300. The springs improve the contact between the body 111 and the tuning plate 300. The spring 4 is simple in its manufacture and has a flexible design and a very good contact with a relatively short distance (approximately 1.5 mm) between the springs 4. Each spring 4 is bent as shown in figure 10 in such a way that the contact between the base 111 and each spring 4 is made only at a point 10 and Not in a large area. Usually, filters for radio base stations tuned using a tuning plate are manufactured using a cast portion with the filter cavities (here called the base 111), a tuning plate 300 and a lid 110. Even when the described modes above they both use a screw to create the capacitance adjustment, other types of adjustment means and capacitance means may be employed. The use of the screw provides especially a more convenient method to automatically test by using robots that simply rotate the screw. This also means that when the filter is tuned, only one tool is required. Although the embodiments described above both employ one screw to create the capacitance adjustment, other types of adjustment means and capacitance means may be employed. The use of the screw especially offers a more convenient method for automatic testing by using robots to simply rotate the screw. It also means that when the filter is tuned, only one tool is required. It is evident that one or more tuning plates can be placed on a filter, that each tuning plate has one or more tuning points, that the springs can be separate elements fastened on the tuning plate or the body, that a filter can having one or several cavities and that the number of projections and valleys in the waveform parts of the tuning plate can be one or several without departing from the spirit of the invention. The embodiments described above serve merely as an illustration but do not limit the present invention. It will be evident to a person with certain knowledge in the art that one can leave the modalities described above without departing from the spirit and scope of the invention. Accordingly, the invention should not be considered as limited to the examples described, but should instead be considered as encompassing the scope of the following claims.

Claims (1)

1. CLAIMS A tuning device arranged in a tuning plate (300) for use in radio equipment where the equipment is tuned by the use of a force directed substantially perpendicular to said tuning plate, comprising a) several parts in recess (11,12), said parts are recessed in relation to said plate, each part is designed in such a way as to form a corrugated surface converging towards a common point, b) a central plate (3) integrated with each of said recessed portions (11, 12) in order to receive said tuning force, said recessed portions are separated from each other but integrated with said central plate (3) and converge towards a center of the central plate. A tuning device according to claim 1, wherein said central plate (3) is equipped with a raised part (3a) in the center of the plate in order to receive said tuning force. A tuning device according to claims 1-2, wherein a recess part (1) consists of a substantially triangular portion whose upper part is truncated and integrated with said central plate, the base portion of said triangular portion is integrated with the tuning plate (300). A tuning device according to claim 3, wherein said triangular portion is corrugated in the form of a wave pattern. A tuning device according to claim 4, wherein said waveform pattern is asymmetric such that a part directed downwardly relative to said tuning force has a different length than an upwardly directed part. A tuning plate (300) in a radio equipment comprising several cavities, whose electrical properties must be tuned, and including various tuning devices in accordance with that claimed in each of claims 1-5, wherein the devices of Tuning (401) are arranged side by side integrated in the tuning plate and placed in relation to each of the cavities. A tuning plate according to claim 6, wherein spring-like elements are arranged between two adjacently arranged tuning devices (401, FIG. 7) which are in contact with the radio equipment in order to protect the radio-controlled plate. tuning. A tuning plate according to claim 7, wherein several spring-type elements (4) are arranged in parallel, side by side, between two adjacent tuning devices (401).