A tunable filter with constant absolute bandwidth

Abstract

The application relates to the technical field of filter mounting, in particular to an adjustable center frequency and constant absolute bandwidth adjustable filter, which comprises a filter shell, a cover plate is fixedly installed at the back side of the filter shell, a fixing strip is arranged at the back side of the cover plate, a plurality of mounting holes are formed in the fixing strip, a clamping mechanism and a limiting mechanism are further arranged, the cover plate is stably installed on the fixing strip through the clamping mechanism and the limiting mechanism, the installation of the filter shell and the cover plate can be realized regardless of whether the fixing strip is vertically installed or horizontally installed, the operator can be prevented from using complex fixing tools and fixing steps, and the stability and reliability of the equipment are improved. Regardless of whether the fixing strip is vertically installed or horizontally installed, the installation mode can adapt to different installation requirements, and the flexibility of the equipment is improved.

Description

Technical Field

[0001] This invention relates to the field of filter installation technology, specifically to a filter with adjustable center frequency and constant absolute bandwidth. Background Technology

[0002] A center-frequency adjustable, absolute bandwidth constant adjustable filter is a high-performance filter that maintains a constant bandwidth while adjusting the center frequency. It is primarily based on technologies such as varactor diodes, mechanical tuning, microelectromechanical systems (MEMS), and digital tuning. The resonant frequency of the filter is affected by changing the applied voltage to adjust its capacitance value. The resonant frequency can also be changed by rotating or sliding the resonant element. High-precision, high-reliability frequency tuning is achieved through minute changes in the mechanical structure. In digital signal processing or software-defined radio systems, the frequency response is adjusted by changing the filter coefficients.

[0003] When using a filter to filter signals in a circuit, it needs to be installed inside the electrical equipment. Generally, the filter's mounting holes need to be aligned with the screw holes on the base plate, and the filter is then secured to the base plate using screws. During this process, the operator needs to have all the necessary screws and tools ready, and then tighten the filter one by one at each of the four corners. If the screws are tightened too much, it may cause mechanical stress to the filter. This stress may damage internal components or degrade performance, especially for sensitive components, where the impact may be more significant. Furthermore, this installation method may not be suitable for equipment that requires frequent filter replacements, as each replacement requires removing the screws, making the operation cumbersome and increasing maintenance costs and time. Summary of the Invention

[0004] The purpose of this invention is to provide a filter with adjustable center frequency and constant absolute bandwidth to solve the problems mentioned in the background art.

[0005] The technical solution adopted by this application to solve its technical problem is: a filter with adjustable center frequency and constant absolute bandwidth, comprising: a filter housing, a cover plate fixedly installed on the rear side of the filter housing, a fixing strip provided on the rear side of the cover plate, and a plurality of mounting holes provided on the fixing strip, characterized in that it further comprises: A snap-fit ​​mechanism is provided on the cover plate. The snap-fit ​​mechanism includes a pressing component and a fixing component. The pressing component includes movable columns symmetrically arranged inside the cover plate. The fixing component includes a synchronization block fixedly arranged at the end of the movable column. Each synchronization block is provided with a claw. The snap-fit ​​mechanism is used to install the filter housing and the cover plate onto the fixing strip. A limiting mechanism is provided on the cover plate. The limiting mechanism includes a fixing block fixedly disposed in the middle of the cover plate, and abutment blocks are symmetrically disposed on both sides of the fixing block. The limiting mechanism is used to fix the position of the cover plate.

[0006] Preferably, an input terminal is fixedly provided on one side of the filter housing, an output terminal is provided on the other side of the filter housing, and a resonant element and a variable element are provided inside the filter housing cavity.

[0007] Preferably, the pressing assembly further includes a cylindrical groove symmetrically formed on the cover plate, a pressing column slidably connected to the inner wall of the cylindrical groove, a set of fixing plates symmetrically fixed at the end of the pressing column, each fixing plate having a through hole, and a connecting shaft fixedly formed inside the through hole.

[0008] Preferably, the cover plate is further provided with a movable cavity 1, which is connected to a cylindrical groove 1. The end of the pressing column, the fixing piece 1, and the connecting shaft are all located in the movable cavity 1. A cylindrical groove 2 is provided on one side of the movable cavity 1 and is connected to it. The inner wall of the cylindrical groove 2 is slidably connected to the movable column.

[0009] Preferably, a movable cavity is provided in the middle of the cylindrical groove, and a limit ring is provided in each movable cavity. The limit ring is fixed to the outer surface of the movable column, and a spring is sleeved on the outer surface of the movable column. The spring is located in the movable cavity.

[0010] Preferably, a second fixing plate is fixedly provided on the top of the movable column, the second fixing plate is located between the first fixing plates, the second fixing plate has a through straight groove, the straight groove is inclined, the inner wall of the straight groove is slidably connected to the connecting shaft, and the straight groove is penetrated by the connecting shaft.

[0011] Preferably, the fixing component further includes grooves symmetrically formed on the rear side of the cover plate, the inner wall of the grooves being slidably connected to the synchronization block.

[0012] Preferably, the limiting mechanism further includes square grooves symmetrically formed on the fixed block, and a movable block is slidably disposed on the inner wall of the square groove, with the ends of the movable block being fixedly connected to the abutment block.

[0013] Preferably, each of the square grooves has a circular groove communicating with it at its bottom, and the circular grooves have symmetrical sliding grooves on their walls. A second movable block is slidably disposed on the inner wall of the circular groove, and one side of the second movable block is fixedly connected to the first movable block.

[0014] Preferably, the outer surface of the movable block two is symmetrically provided with sliders, the outer surface of the sliders slides in the groove, and the outer surface of the movable block two is fitted with a spring two, which is located in the inner cavity of the square groove.

[0015] The beneficial effects of this application are: This application provides a filter with adjustable center frequency and constant absolute bandwidth. Through the combined use of a pressing component and a fixing component, it enables the rapid installation and removal of the filter housing and cover from the fixing strip. The pressing component responds to external pressure from the operator, driving the fixing component to lock onto the fixing strip, thereby ensuring a secure installation of the filter. The fixing component includes a synchronizing block and claws, used to lock onto the fixing strip under pressure, preventing the filter from loosening. This not only simplifies the installation and removal process of the filter but also improves the vertical stability of the equipment, preventing the cover from shaking up and down.

[0016] This application provides a filter with adjustable center frequency and constant absolute bandwidth. A limiting mechanism engages with the mounting holes of a fixing strip, horizontally securing the cover plate and preventing it from swaying. By using both horizontal and vertical methods to stably mount the cover plate onto the fixing strip, the filter housing and cover plate can be installed regardless of whether the fixing strip is installed vertically or horizontally. This eliminates the need for operators to use complex fixing tools and procedures, improving the stability and reliability of the equipment. This installation method adapts to different installation needs, regardless of whether the fixing strip is installed vertically or horizontally, increasing the flexibility of the equipment.

[0017] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. These will be further described in detail below with reference to figures. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cover plate structure after the fixing strip is removed according to the present invention; Figure 3 This is a schematic diagram of the overall cross-section structure of the cover plate of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram at point A; Figure 5 This is a partial structural diagram of the pressing component of the snap-fit ​​mechanism of the present invention; Figure 6 This is a schematic diagram of a partial mechanism within the cover plate cavity of the present invention; Figure 7 This is a schematic diagram of the overall structure of the present invention from another perspective; Figure 8 For the present invention Figure 7 Enlarged structural diagram at point B; Figure 9 This is a schematic diagram of the limiting mechanism structure of the present invention; Figure 10 For the present invention Figure 9 A magnified structural diagram at point C.

[0019] Drawing number explanation: 1. Filter housing; 2. Cover plate; 3. Input end; 4. Output end; 5. Fixing strip; 6. Mounting hole; 7. Snap-fit ​​mechanism; 8. Pressing assembly; 9. Cylindrical groove one; 10. Pressing post; 11. Fixing piece one; 12. Through hole; 13. Connecting shaft; 14. Movable cavity one; 15. Cylindrical groove two; 16. Movable post; 17. Limiting ring; 18. Fixing piece two; 19. Straight groove; 20. Movable cavity two; 21. Spring one; 22. Fixing assembly; 23. Groove; 24. Synchronizing block; 25. Claw; 26. Limiting mechanism; 27. Fixing block; 28. Square groove; 29. ​​Movable block one; 30. Circular groove; 31. Slide groove; 32. Movable block two; 33. Sliding block; 34. Spring two; 35. Abutment block. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0022] Please refer to Figures 1 to 10 A filter with adjustable center frequency and constant absolute bandwidth includes: a filter housing 1, which provides physical protection for the sensitive electronic components inside the filter, preventing damage to the components from external impacts, vibrations, or environmental factors; a cover plate 2 fixedly installed on the rear side of the filter housing 1, which covers the open end of the filter to ensure isolation between the internal circuit and the external environment, preventing dust, moisture, or other impurities from entering the filter; the cover plate 2 is usually fixed to the housing by screws or clips, providing additional support for the internal components and enhancing the overall structural strength of the filter; and a fixing strip 5 is provided on the rear side of the cover plate 2, with several mounting holes 6 for mounting the fixing strip 5 to the inner wall of the electrical equipment.

[0023] Please refer to Figures 1 to 10A filter with adjustable center frequency and constant absolute bandwidth further includes a locking mechanism 7, which is disposed on a cover plate 2. The locking mechanism 7 includes a pressing component 8 and a fixing component 22. The pressing component 8 includes movable columns 16 symmetrically arranged within the cover plate 2. The fixing component 22 includes synchronization blocks 24 fixedly disposed at the ends of the movable columns 16. Each synchronization block 24 is provided with a claw 25. The locking mechanism 7 is used to install the filter housing 1 and the cover plate 2 onto the fixing strip 5. Through the cooperation of the pressing component 8 and the fixing component 22, the locking mechanism 7 enables the quick installation and removal of the filter housing 1 and the cover plate 2 from the fixing strip 5. The pressing component 8 is responsible for responding to external pressure from the operator, driving the fixing component 22 to lock the fixing strip 5, thereby ensuring the filter is securely installed. The fixing component 22 includes synchronization blocks 24 and claws 25, which are used to lock the fixing strip 5 under pressure to prevent the filter from loosening. This not only simplifies the installation and removal process of the filter but also improves the vertical stability of the equipment and prevents the cover plate 2 from shaking vertically.

[0024] Please refer to Figures 1 to 10 A filter with adjustable center frequency and constant absolute bandwidth further includes a limiting mechanism 26, which is disposed on a cover plate 2. The limiting mechanism 26 includes a fixing block 27 fixedly disposed in the middle of the cover plate 2, and abutment blocks 35 symmetrically disposed on both sides of the fixing block 27. The limiting mechanism 26 is used to fix the position of the cover plate 2. The abutment blocks 35 are symmetrically disposed on both sides of the fixing block 27 and cooperate with the mounting holes 6 of the fixing strip 5 to ensure a stable connection of the cover plate 2. The design of the abutment blocks 35 improves the lateral stability and reliability of the device and prevents the cover plate 2 from swaying left and right.

[0025] It is important to emphasize that the filter housing 1 has an input terminal 3 fixedly mounted on one side and an output terminal 4 mounted on the other side. The interior of the filter housing 1 houses resonant elements and variable elements. Input terminal 3 receives the signal to be processed, and output terminal 4 transmits the processed signal. These elements act as a bridge for signal transmission within the filter, ensuring smooth signal entry and exit. Resonant elements, such as inductors and capacitors, together form a resonant circuit that determines the filter's center frequency. Through their impedance characteristics, they allow signals of specific frequencies to pass through while blocking or attenuating signals of other frequencies, thus achieving the filtering function. Variable elements, such as varactor diodes and adjustable inductors, are used to adjust the filter's inductance or capacitance values, thereby achieving dynamic control of the filter's characteristics. This design allows the filter to adjust its operating frequency or bandwidth as needed, improving the flexibility and practicality of the device.

[0026] For further details, please refer to Figures 2 to 7The pressing assembly 8 also includes symmetrically formed cylindrical grooves 9 on the cover plate 2. A pressing post 10 is slidably connected to the inner wall of the cylindrical groove 9. A set of fixing plates 11 are symmetrically fixed at the ends of the pressing posts 10. Each fixing plate 11 has a through hole 12, and a connecting shaft 13 is fixedly installed through the through hole 12. The cover plate 2 also has a movable cavity 14, which is connected to the cylindrical groove 9. The ends of the pressing posts 10, the fixing plates 11, and the connecting shaft 13 are all located in the movable cavity 14. A cylindrical groove 15 is provided on one side of the movable cavity 14, and the inner wall of the cylindrical groove 15 is slidably connected to the movable post 16. A movable cavity 20 is provided in the middle of the cylindrical groove 15. Each movable cavity is provided with a limit ring 17, which is fixed to the outer surface of the movable post 16. A spring 21 is sleeved on the outer surface of the movable post 16 and is located in the movable cavity 20.

[0027] The movable column 16 has a fixed fixing plate 28 fixedly installed on its top, located between the fixing plates 11. A straight groove 19 is formed through the fixing plate 28, and the groove 19 is inclined. The inner wall of the groove 19 is slidably connected to the connecting shaft 13, and the connecting shaft 13 penetrates the groove 19. It should be noted that the fixing assembly 22 also includes symmetrically formed grooves 23 on the rear side of the cover plate 2, and the inner wall of the grooves 23 is slidably connected to the synchronization block 24.

[0028] By simultaneously pinching the pressing column 10, the connecting shaft 13 on the movable plate 1 slides into the straight groove 19 of the connecting plate 2. The straight groove 19 is tilted, causing the connecting shaft 13 to lift the movable column 16. Under the constraint of the limiting ring 17, the spring 21 is compressed. At this time, the fixing block 27 of the fixing component 22 is driven by the movable column 16, causing the two claws 25 to move away from each other. There is sufficient distance between the claws 25 to engage with the fixing strip 5. After the claws 25 intersect with the inclined surfaces of the fixing strip 5, the pressing column 10 is released. The spring 21 is then released, causing the movable column 16 to reset and simultaneously engaging the claws 25 with the fixing strip 5. The entire operation is simple and straightforward; simply pinching the pressing column 10 completes the installation and fixing of the filter. Through the coordinated work of the connecting shaft 13, the movable column 16, and the spring, the claws 25 are securely engaged with the fixing strip 5, improving the longitudinal stability of the equipment.

[0029] Furthermore, please refer to the following for details. Figures 8 to 10The limiting mechanism 26 also includes square grooves 28 symmetrically formed on the fixed block 27. Movable blocks 29 are slidably disposed on the inner wall of the square grooves 28, and the ends of the movable blocks 29 are fixedly connected to the abutment blocks 35. Circular grooves 30 are formed at the bottom of each square groove 28, communicating with them. Sliding grooves 31 are symmetrically formed on the walls of the circular grooves 30. Movable blocks 32 are slidably disposed on the inner wall of the circular grooves 30, and one side of the movable blocks 32 is fixedly connected to the movable blocks 29. Sliding sliders 33 are symmetrically disposed on the outer surface of the movable blocks 32, sliding within the sliding grooves 31. Springs 34 are fitted onto the outer surface of the movable blocks 32, and the springs 34 are located within the inner cavity of the square grooves 28.

[0030] When the operator aligns the fixing block 27 with the mounting hole 6 of the fixing strip 5, the fixing block 27 gradually approaches the mounting hole 6, continuing to align until the abutment block 35 fits against the mounting hole 6. At this point, the opening of the mounting hole 6 presses against the inclined surface of the abutment block 35, causing the abutment block 35 to press the movable block 29 into the square groove 28. Simultaneously, the movable block 32 slides synchronously into the circular groove 30 via the slider 33, until the distance between the two abutment blocks 35 equals the distance between the mounting holes 6. At this point, the cover plate 2 is horizontally fixed, preventing the cover plate 2 from wobbling left and right. By horizontally and vertically fixing the cover plate 2 onto the fixing strip 5, the filter housing 1 and the cover plate 2 can be installed regardless of whether the fixing strip 5 is installed vertically or horizontally. This avoids the need for operators to use complex fixing tools and steps, improving the stability and reliability of the equipment. Whether the fixing strip 5 is installed vertically or horizontally, this installation method can adapt to different installation needs, improving the flexibility of the equipment.

[0031] Based on all the above embodiments, the working principle of the present invention is as follows: The operator simultaneously pinches the pressing column 10, causing the connecting shaft 13 on the movable plate one to slide into the straight groove 19 of the connecting plate two. The straight groove 19 is tilted, causing the connecting shaft 13 to lift the movable column 16. Under the constraint of the limiting ring 17, the spring 21 is compressed. At this time, the fixing block 27 of the fixing component 22 is driven by the movable column 16, causing the two claws 25 to move away from each other. There is sufficient distance between the claws 25 to engage with the fixing strip 5. After the claws 25 intersect with the inclined surfaces of the fixing strip 5, the pressing column 10 is released. The spring 21 is then released, causing the movable column 16 to reset and simultaneously engaging the claws 25 with the fixing strip 5. The entire operation is simple and straightforward; simply pinching the pressing column 10 completes the installation and fixing of the filter. Through the coordinated work of the connecting shaft 13, the movable column 16, and the spring, the claws 25 are securely engaged with the fixing strip 5, improving the longitudinal stability of the equipment. While the operator holds the pressing column 10, the fixing block 27 is aligned with the mounting hole 6 of the fixing strip 5 for installation. The fixing block 27 will gradually approach the mounting hole 6, continuing to align until the abutment block 35 fits against the mounting hole 6. At this time, the opening of the mounting hole 6 will press against the inclined surface of the abutment block 35, causing the abutment block 35 to press the movable block 29 to slide in the square groove 28. At the same time, the movable block 32 slides synchronously in the circular groove 30 through the slider 33 until the distance between the two abutment blocks 35 is equal to the distance between the mounting holes 6. At this time, the cover plate 2 is horizontally fixed, preventing the cover plate 2 from wobbling left and right. By horizontally and vertically fixing the cover plate 2 on the fixing strip 5, the filter housing 1 and the cover plate 2 can be installed regardless of whether the fixing strip 5 is installed vertically or horizontally. This avoids the need for the operator to use complicated fixing tools and steps, improving the stability and reliability of the equipment. Regardless of whether the fixing strip 5 is installed vertically or horizontally, this installation method can adapt to different installation needs, improving the flexibility of the equipment.

[0032] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary. Under the framework of this invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0033] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A filter with adjustable center frequency and constant absolute bandwidth, comprising: A filter housing (1), a cover plate (2) is fixedly installed on the rear side of the filter housing (1), a fixing strip (5) is provided on the rear side of the cover plate (2), and a plurality of mounting holes (6) are provided on the fixing strip (5), characterized in that it further includes: The snap-fit ​​mechanism (7) is disposed on the cover plate (2). The snap-fit ​​mechanism (7) includes a pressing component (8) and a fixing component (22). The pressing component (8) includes movable columns (16) symmetrically disposed in the cover plate (2). The fixing component (22) includes a synchronization block (24) fixedly disposed at the end of the movable column (16). Each synchronization block (24) is provided with a claw (25). The snap-fit ​​mechanism (7) is used to install the filter housing (1) and the cover plate (2) onto the fixing strip (5). The limiting mechanism (26) is set on the cover plate (2). The limiting mechanism (26) includes a fixing block (27) fixedly set in the middle of the cover plate (2). Abutment blocks (35) are symmetrically arranged on both sides of the fixing block (27). The limiting mechanism (26) is used to fix the position of the cover plate (2).

2. The center frequency adjustable and absolute bandwidth constant adjustable filter according to claim 1, characterized in that, The filter housing (1) has an input terminal (3) fixedly installed on one side and an output terminal (4) installed on the other side. The filter housing (1) has a resonant element and a variable element installed inside the cavity.

3. The center frequency adjustable and absolute bandwidth constant adjustable filter according to claim 1, characterized in that, The pressing assembly (8) also includes a cylindrical groove (9) symmetrically opened on the cover plate (2). A pressing column (10) is slidably connected to the inner wall of the cylindrical groove (9). A set of fixing plates (11) are symmetrically fixed at the end of the pressing column (10). A through hole (12) is opened through each fixing plate (11). A connecting shaft (13) is fixedly installed through the through hole (12).

4. A filter with adjustable center frequency and constant absolute bandwidth according to claim 3, characterized in that, The cover plate (2) is also provided with a movable cavity (14), which is connected to the cylindrical groove (9). The end of the pressing column (10), the fixing piece (11) and the connecting shaft (13) are all located in the movable cavity (14). A cylindrical groove (15) is provided on one side of the movable cavity (14) and is connected to it. The inner wall of the cylindrical groove (15) is slidably connected to the movable column (16).

5. A filter with adjustable center frequency and constant absolute bandwidth according to claim 4, characterized in that, The cylindrical groove 2 (15) is provided with a movable cavity 2 (20) in the middle. Each movable cavity is provided with a limit ring (17). The limit ring (17) is fixed to the outer surface of the movable column (16). The outer surface of the movable column (16) is fitted with a spring 1 (21). The spring 1 (21) is located in the movable cavity 2 (20).

6. A filter with adjustable center frequency and constant absolute bandwidth according to claim 5, characterized in that, The top of the movable column (16) is fixedly provided with a second fixing plate (18), which is located between the first fixing plate (11). A straight groove (19) is opened through the second fixing plate (18). The straight groove (19) is inclined and the inner wall of the straight groove (19) is slidably connected to the connecting shaft (13). The straight groove (19) is penetrated by the connecting shaft (13).

7. A filter with adjustable center frequency and constant absolute bandwidth according to claim 1, characterized in that, The fixing component (22) also includes grooves (23) symmetrically opened on the rear side of the cover plate (2), and the inner wall of the groove (23) is slidably connected to the synchronization block (24).

8. A filter with adjustable center frequency and constant absolute bandwidth according to claim 1, characterized in that, The limiting mechanism (26) also includes a square groove (28) symmetrically opened on the fixed block (27), and a movable block (29) is slidably arranged on the inner wall of the square groove (28), and the ends of the movable block (29) are fixedly connected to the abutment block (35).

9. A filter with adjustable center frequency and constant absolute bandwidth according to claim 8, characterized in that, The bottom of the square groove (28) is provided with a circular groove (30) that communicates with it. The circular groove (30) is provided with a sliding groove (31) symmetrically on the groove wall. The inner wall of the circular groove (30) is provided with a movable block two (32), and one side of the movable block two (32) is fixedly connected to the movable block one (29).

10. A filter with adjustable center frequency and constant absolute bandwidth according to claim 9, characterized in that, The outer surface of the movable block 2 (32) is symmetrically provided with sliders (33), the outer surface of the sliders (33) slides in the groove (31), and the outer surface of the movable block 2 (32) is fitted with spring 2 (34), the spring 2 (34) is located in the inner cavity of the square groove (28).

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