Combination system based on frequency hopping filter

Abstract

The invention provides a combining system based on a frequency hopping filter, which comprises a control panel, an adapter plate and a plurality of radio frequency channels, the plurality of radio frequency channels are connected in parallel, each radio frequency channel comprises a frequency hopping filter and a digital switch line module, a first port of the frequency hopping filter is connected with an external radio station, and a second port of the frequency hopping filter is connected with a second radio station; a second port of the frequency hopping filter is connected with a first port of the digital switch line module, and a second port of the digital switch line module is connected with an external antenna in tandem; wherein the frequency hopping filter is used for tracking working frequency data hopping of an external radio station; an EEPROM module is arranged on the control panel and used for storing control codes; the control end of the frequency hopping filter, the control end of the digital switch line module and the control panel are connected with the adapter plate, and are used for calling a control code through the control panel according to the working frequency data of an external radio station to control the digital switch line module to realize the combination of a plurality of radio frequency channels.

Description

Technical Field

[0001] The present invention relates to the technical field of filter combining, and in particular to a combining system based on frequency hopping filters. Background Art

[0002] With the development of modern communication technology, the amount of communication information is increasing, the integration of equipment is increasing, and various communication sites, vehicles and other places have formed the integration and co-location of various wireless communication equipment such as high-power, multi-band, frequency hopping, and spread spectrum, which brings severe tests to the electromagnetic compatibility of the system. In particular, the intermodulation signals generated by the antennas of multiple devices are often very close to the working frequency, making it impossible for the frequency hopping filter to effectively filter them out.

[0003] The use of antenna combiners can significantly reduce the number of antennas and improve the electromagnetic compatibility environment, which not only ensures the communication quality but also reduces the target identification characteristics. Among them, the use of frequency hopping filters to design antenna combiners is a common design method. Compared with the fixed frequency band filter group method, this method can significantly reduce the size of the antenna combiner.

[0004] The existing typical design is an antenna combiner designed with a frequency hopping filter, and the combining scheme is a bridge combining; however, each RF channel needs to use two or more frequency hopping filters through bridge combining, resulting in excessively high costs. Summary of the invention

[0005] The present invention provides a combining system based on a frequency hopping filter, which is used to solve the problem that the existing typical bridge combining system needs to use two or more frequency hopping filters, resulting in excessively high costs.

[0006] According to an embodiment of the present invention, a combining system based on a frequency hopping filter includes:

[0007] A control board, an adapter board and a plurality of radio frequency channels, wherein the plurality of radio frequency channels are connected in parallel, and the radio frequency channels include: a frequency hopping filter and a digital switch line module, wherein a first port of the frequency hopping filter is connected to an external radio station, a second port of the frequency hopping filter is connected to a first port of the digital switch line module, and a second port of the digital switch line module is connected to an external antenna; wherein the frequency hopping filter is used to track the data jump of the working frequency of the external radio station;

[0008] The control board is equipped with an EEPROM module for storing control codes;

[0009] The control end of the frequency hopping filter, the control end of the digital switch line module and the control board are all connected to the adapter board, which is used to control the digital switch line module to realize the combination of several RF channels by retrieving the control code according to the working frequency data of the external radio station through the control board.

[0010] As an embodiment of the present invention, it also includes: a power board, which is connected to the control board and is used to supply power to the system.

[0011] As an embodiment of the present invention, the digital switch line module is any one of a parallel digital switch line, a series digital switch line and a series-parallel digital switch line.

[0012] As an embodiment of the present invention, the parallel digital switch line includes:

[0013] A first line board, a first multidirectional switch, a first parallel line, a second parallel line, a third parallel line, a fourth parallel line and a fifth parallel line, wherein the first parallel line, the second parallel line, the third parallel line, the fourth parallel line and the fifth parallel line are arranged side by side on the first line board, and the lengths of the first parallel line, the second parallel line, the third parallel line, the fourth parallel line and the fifth parallel line increase in an arithmetic progression;

[0014] Two first multidirectional switches are symmetrically arranged on the first line board, wherein one of the first multidirectional switches is connected to the frequency hopping filter, and the other first multidirectional switch is connected to the external antenna. The first multidirectional switch is used to select and connect the corresponding parallel line.

[0015] As an embodiment of the present invention, the series digital switch line includes:

[0016] A second line board, a second multidirectional switch, a first short-circuit wire, a first series wire, a second series wire, a third series wire and a fourth series wire, four second line boards are arranged side by side, the four second line boards are each provided with a first short-circuit wire and two second multidirectional switches, and two adjacent second line boards are connected through the fixed ends of the second directional switches thereon;

[0017] The first short-circuit wire, the first series wire, the second series wire, the third series wire and the fourth series wire are respectively arranged on four second wire boards in sequence, and the lengths of the first short-circuit wire, the first series wire, the second series wire, the third series wire and the fourth series wire increase in an arithmetic progression in sequence.

[0018] As an embodiment of the present invention, the series-parallel digital switch line includes:

[0019] A third line board, a third multidirectional switch, a second short-circuit wire, a first series parallel wire, a second series parallel wire, a third series parallel wire and a fourth series parallel wire, four third line boards are arranged side by side, and the four third line boards are each provided with a second short-circuit wire and two third multidirectional switches, and two adjacent third line boards are connected through the fixed ends of the third directional switches thereon;

[0020] Two first series parallel wires, two second series parallel wires, two third series parallel wires and two fourth series parallel wires are respectively arranged on four third line boards, and the lengths of the first series parallel wires, the second series parallel wires, the third series parallel wires and the fourth series parallel wires increase in an arithmetic progression.

[0021] As an embodiment of the present invention, the first parallel line, the second parallel line, the third parallel line, the fourth parallel line, the fifth parallel line, the first series line, the second series line, the third series line, the fourth series line, the first series-parallel line, the second series-parallel line, the third series-parallel line and the fourth series-parallel line are all digital switch lines.

[0022] As an embodiment of the present invention, control ports of the first multi-directional switch, the second multi-directional switch and the third multi-directional switch are all connected to the adapter board.

[0023] In addition, the present invention also provides a combining method based on a frequency hopping filter, comprising the following steps:

[0024] Get the working frequency data of external radio stations;

[0025] Control the corresponding frequency hopping filter to perform frequency hopping according to the operating frequency data;

[0026] Determine whether there is a control code corresponding to the operating frequency data in the control code data;

[0027] If it exists, the corresponding digital switch line module is controlled according to the control code; if it does not exist, the corresponding control code is determined based on the proximity principle and the corresponding digital switch line module is controlled.

[0028] Compared with the prior art, the present invention has the following beneficial effects: by controlling the corresponding frequency hopping filter to switch the operating frequency and using the control code to adjust the length of the transmission line in the corresponding digital switch line module, the combining method is completed. Only one frequency hopping filter is needed in one RF channel to complete the combining, thereby reducing the use cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an architecture diagram of a combining system according to an embodiment of the present invention;

[0030] Figure 2 A parallel digital switch line according to an embodiment of the present invention;

[0031] Figure 3 A series digital switch line according to an embodiment of the present invention;

[0032] Figure 4 A series-parallel digital switch line according to an embodiment of the present invention;

[0033] Figure 5The Smith impedance characteristic curve of the frequency hopping filter at 30 MHz according to the embodiment of the present invention;

[0034] Figure 6 This is a diagram of a test structure for the length of a combined transmission line of a frequency hopping filter according to an embodiment of the present invention;

[0035] Figure 7 The automatic design test architecture diagram of an embodiment of the present invention;

[0036] Figure 8 A manual design flow chart for an embodiment of the present invention;

[0037] Fig. 9 The automatic design flow chart of the embodiment of the present invention;

[0038] Fig.10 A schematic diagram of a transmission-type digital switch line architecture according to an embodiment of the present invention;

[0039] Fig.11 A schematic diagram of a rotary digital switch wiring diagram according to an embodiment of the present invention;

[0040] Fig.12 Transmission line impedance diagram when the load is open

[0041] Fig.13 4 is a control flow chart of an embodiment of the present invention.

[0042] In the above drawings: 1. control board; 2. adapter board; 3. frequency hopping filter; 4. power board; 5. digital switch line module; 6. EEPROM module, 7. first multi-directional switch; 8. first parallel line; 9. second parallel line; 10. third parallel line; 11. fourth parallel line; 12. fifth parallel line; 13. first line board; 14. second line board; 15. second multi-directional switch; 16. first short-circuit line; 17. first series line; 18. second series line; 19. third series line; 20. fourth series line; 21. third multi-directional switch; 22. third line board; 23. second short-circuit line; 24. first series parallel line; 25. second series parallel line; 26. third series parallel line; 27. fourth series parallel line. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0044] like Figures 1 to 12 As shown, the present invention provides a combining system based on a frequency hopping filter, comprising:

[0045] A control board 1, an adapter board 2 and a plurality of radio frequency channels, wherein the plurality of radio frequency channels are connected in parallel, and the radio frequency channels include: a frequency hopping filter 3 and a digital switch line module 5, wherein a first port of the frequency hopping filter 3 is connected to an external radio station, a second port of the frequency hopping filter 3 is connected to a first port of the digital switch line module 5, and a second port of the digital switch line module 5 is connected to an external antenna; wherein the frequency hopping filter is used to track the data jump of the working frequency of the external radio station;

[0046] The control board 1 is provided with an EEPROM module 6 for storing control codes;

[0047] The control end of the frequency hopping filter 3, the control end of the digital switch line module 5 and the control board 1 are all connected to the adapter board 2, which is used to control the digital switch line module to realize the combination of several radio frequency channels by calling the control code according to the working frequency data of the external radio station through the control board;

[0048] It also includes: a power board 4, which is connected to the control board 2 and is used to supply power to the system;

[0049] Working principle of the above technical solution: The principle of the present invention is based on the impedance transformation of the transmission line (digital switch line module 5). First, the transmission line impedance equation is analyzed, and the calculation formula is as follows:

[0050]

[0051] When the load is open circuit, Z L =∞ (considering a lossless transmission line), Z in The calculation formula is as follows:

[0052] Z in =-jZ0cotβl

[0053] Therefore, at any length l, its impedance is a pure imaginary number, and the impedance relationship is as follows: Fig.12 As shown. It can be seen that by changing the length of the transmission line, the input impedance can be "infinite";

[0054] like Figure 1 As shown, the present invention takes the channel combination of two RF channels as an example, and analyzes the input impedance at the working frequency point f1 of one of the channels. No matter how the transmission line length of channel 1 changes, it should be approximately equal to the standard impedance Z0 at the working frequency point f1. The transmission line length in the digital switch line module 5 is adjusted so that the impedance at f2 (the working frequency point of another RF channel) is "infinite". Similarly, the input impedance at the working frequency point f2 of channel 2 is analyzed. No matter how the transmission line length of channel 2 changes, it should be approximately equal to the standard impedance Z0 at the working frequency point f2. The transmission line length is adjusted so that the impedance at f1 is "infinite". The two groups of transmission lines that meet the above requirements are the optimal combined matching transmission lines. The following analyzes how to use the Smith chart to analyze the design:

[0055] According to the definition of reflection coefficient, the calculation formula is as follows:

[0056]

[0057] Normalized impedance is defined and calculated as follows:

[0058]

[0059] Combining the above two equations, we can get

[0060]

[0061] According to Euler's formula, we can get

[0062] e jβl =cosβl+j sinβl

[0063] The Smith chart representation of the transmission line equation is obtained, and the calculation formula is as follows:

[0064]

[0065] From the Smith chart representation equation of the transmission line equation, it can be seen that changing the line length l corresponds to rotating the phase angle in the Smith chart. When l is half a wavelength, it corresponds to one rotation of the Smith chart.

[0066] like Figure 5 The impedance characteristic curve of the frequency hopping filter working at 30MHz is shown, the dotted circle is the 1.2 standing wave circle, the circle is the working frequency band of the frequency hopping filter, and point M is 33MHz; increase the transmission line length in the digital switch line module 5, and point M rotates toward the open end along the equal Γ circle in the direction of the arrow; after point M rotates to the open end, the 30MHz frequency hopping filter can achieve the optimal combining effect with the 33MHz channel; specifically, the control board obtains the working frequency data required for combining by the external radio station, controls the corresponding frequency hopping filter 3 to switch the working frequency, and at the same time selects the control code corresponding to the control code data stored in the EEPROM module according to the working frequency data, and adjusts the transmission line length in the digital switch line module 5 through the control code, thereby completing the combining;

[0067] Beneficial effects of the above technical solution: Through the above technical solution, by controlling the corresponding frequency hopping filter 3 to switch the working frequency, and using the control code to adjust the transmission line length in the digital switch line module 5, the combining method is completed. In one RF channel, only one frequency hopping filter 3 is needed to complete the combining, thereby reducing the use cost.

[0068] In one embodiment, the digital switch line module 5 is any one of a parallel digital switch line, a series digital switch line, and a series-parallel digital switch line;

[0069] The parallel digital switch line includes:

[0070] A first line board 13, a first multidirectional switch 7, a first parallel line 8, a second parallel line 9, a third parallel line 10, a fourth parallel line 11 and a fifth parallel line 12. The first line board 13 is provided with the first parallel line 8, the second parallel line 9, the third parallel line 10, the fourth parallel line 11 and the fifth parallel line 12 in parallel. The lengths of the first parallel line 8, the second parallel line 9, the third parallel line 10, the fourth parallel line 11 and the fifth parallel line 12 increase in an arithmetic progression.

[0071] Two first multidirectional switches 7 are symmetrically arranged on the first line board 13, one of which is connected to the frequency hopping filter 3, and the other is connected to the external antenna. The first multidirectional switch 7 is used to select and connect the corresponding parallel line;

[0072] The series digital switch line includes:

[0073] A second line board 14, a second multidirectional switch 15, a first short-circuit wire 16, a first series line 17, a second series line 18, a third series line 19 and a fourth series line 20, four second line boards 14 are arranged side by side, the four second line boards 14 are each provided with a first short-circuit wire 16 and two second multidirectional switches 15, and two adjacent second line boards 14 are connected via the fixed ends of the second directional switches 15 thereon;

[0074] The first short-circuit wire 16, the first series wire 17, the second series wire 18, the third series wire 19 and the fourth series wire 20 are respectively arranged on the four second wire plates 14, and the lengths of the first short-circuit wire 16, the first series wire 17, the second series wire 18, the third series wire 19 and the fourth series wire 20 are increased in an arithmetic progression.

[0075] The series-parallel digital switch line includes:

[0076] A third line board 22, a third multidirectional switch 21, a second short-circuit wire 23, a first series parallel wire 24, a second series parallel wire 25, a third series parallel wire 26 and a fourth series parallel wire 27, four third line boards 22 are arranged side by side, and the four third line boards 22 are each provided with a second short-circuit wire 23 and two third multidirectional switches 21, and two adjacent third line boards 22 are connected through the fixed ends of the third directional switches 21 thereon;

[0077] Two first series parallel wires 24, two second series parallel wires 25, two third series parallel wires 26 and two fourth series parallel wires 27 are respectively arranged on four third line boards 22, and the lengths of the first series parallel wires 24, the second series parallel wires 25, the third series parallel wires 26 and the fourth series parallel wires 27 are increased in an arithmetic progression.

[0078] The first parallel line 8, the second parallel line 9, the third parallel line 10, the fourth parallel line 11, the fifth parallel line 12, the first series line 17, the second series line 18, the third series line 19, the fourth series line 20, the first series parallel line 24, the second series parallel line 25, the third series parallel line 26 and the fourth series parallel line 27 are all digital switch lines;

[0079] The control ports of the first multidirectional switch 7, the second multidirectional switch 15 and the third multidirectional switch 21 are all connected to the adapter board 2;

[0080] The working principle of the above technical solution: wherein the method for determining the control code data includes: a manual design method and an automatic design method (both taking two RF channels as examples); wherein the manual design method includes the following steps (such as Figure 8 shown):

[0081] Sh1: Design the data table of the two-channel combined transmission line shown in Table 1, the first row represents the operating frequency of the frequency hopping filter of one of the RF channels (hereinafter referred to as channel 1), and the first column represents the operating frequency of the frequency hopping filter of the other RF channel (hereinafter referred to as channel 2);

[0082] Sh2: Press Figure 6 As shown in the test architecture diagram (or use software simulation), set the frequency hopping filter of channel 1 to 30MHz and its impedance characteristics as shown in Figure 5 As shown, the transmission line length of the corresponding digital switch line module 5 is changed so that the 33MHz frequency point is rotated to the open end of the Smith chart, that is, after this transmission line transformation, the 33MHz frequency point impedance can be converted to "infinity"; the transmission line length at this time is recorded in the second column and third row of Table 1 (two identical frequencies cannot be combined, and generally a frequency interval of more than 10% needs to be maintained, so the second row and second column do not need to be filled in);

[0083] Sh3: Change the length of the transmission line, repeat step Sh2, rotate the 37MHz, 41MHz…88MHz frequency points to the open end of the Smith chart in 10% frequency steps, and record the corresponding transmission line lengths in the second column of Table 1;

[0084] Sh4: Change the frequency of the frequency hopping filter of channel 1 to 37MHz, 41MHz...88MHz in 10% frequency steps, repeat steps Sh2 and Sh3 to complete the transmission line lengths corresponding to all the combined frequency combinations in Table 1, and obtain Table 2;

[0085] Sh5: Analyze the above transmission line length table and discretize it (generally discretized into 5 or more types). For example, discretize the data into 1000, 800, 600, 400, and 200, as shown in Table 3.

[0086] Sh6: Verify the combining index for the data with large errors in the above discretized transmission line length table. If the index requirements are not met, increase the discrete sample and reduce the discrete error until the combining index meets the design requirements.

[0087] Sh7: Based on the above verified discretized transmission line length, a parallel digital switch line is designed, such as Figure 2 As shown;

[0088] Sh8: The parallel digital switch line design is completed, and the parallel digital switch line control code (i.e., the corresponding relationship between the input control code and the conductive transmission line) is obtained. The parallel digital switch line control code is used to replace the discrete data of the transmission line length in the discrete transmission line length table, and the parallel digital switch line control code table (control code data) is obtained, as shown in Table 4;

[0089] Sh9: Write the parallel digital switch line control code table into the EEPROM module on the control board 1;

[0090] Table 1: Data table of two-channel combined transmission line length

[0091] 30 33 37 41 46 51 57 63 70 77 88 30 <![CDATA[l max ]]> 33 37 41 46 51 57 63 70 77 88 <![CDATA[l min ]]>

[0092] Table 2: Data of two-way transmission line length in the 30MHz-88MHz frequency band

[0093]

[0094]

[0095] Table 3: Discrete data of two-way transmission line length in the 30MHz-88MHz frequency band

[0096] 30 33 37 41 46 51 57 63 70 77 88 30 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 33 800 600 800 800 800 800 800 800 800 800 37 600 800 600 600 600 600 600 600 600 600 41 600 600 600 400 400 400 400 400 400 400 46 400 400 400 600 400 400 400 400 400 400 51 400 400 400 400 400 200 400 400 400 400 57 400 400 400 400 400 400 200 200 200 200 63 200 200 200 200 200 400 400 200 200 200 70 200 200 200 200 200 200 200 200 200 200 77 200 200 200 200 200 200 200 200 200 200 88 200 200 200 200 200 200 200 200 200 200

[0097] Table 4: 30MHz-88MHz frequency band two-way transmission line discrete data corresponding to parallel digital switch line control code

[0098] 30 33 37 41 46 51 57 63 70 77 88 30 001 001 001 001 001 001 001 001 001 001 33 010 011 010 010 010 010 010 010 010 010 37 011 010 011 011 011 011 011 011 011 011 41 011 011 011 100 100 100 100 100 100 100 46 100 100 100 011 100 100 100 100 100 100 51 100 100 100 100 100 101 100 100 100 100 57 100 100 100 100 100 100 101 101 101 101 63 101 101 101 101 101 100 100 101 101 101 70 101 101 101 101 101 101 101 101 101 101 77 101 101 101 101 101 101 101 101 101 101 88 101 101 101 101 101 101 101 101 101 101

[0099] The automatic design method includes the following steps (such as Fig. 9 shown):

[0100] Sa1: Press Figure 6 As shown in the test architecture diagram (or software simulation), follow step Sh2 to manually test (or simulate) the length of the combined transmission line required for combining the lowest frequency point (30MHz) and the highest frequency point (88MHz) of the working frequency band, that is, the minimum transmission line length l required for combining. min and the maximum transmission line length l max(i.e., the twelfth row in the second column and the second row in the twelfth column in Table 1);

[0101] Sa2: According to the minimum transmission line length l in step Sa1 min and the maximum transmission line length l max Design a series digital switch line, and design the transmission line length of each bit of the series digital switch line according to an arithmetic progression;

[0102] Sa3: Figure 7 As shown, the frequency of the frequency hopping filter of the combining channel 1 and channel 2 is controlled by the automatic control tool to be f1 and f2 respectively. In this state, all working states of the series digital switch line (that is, all transmission lines of different lengths that can be combined) are traversed, and the series digital switch line with the best combining performance and meeting the design requirements (such as Figure 3 The control code shown);

[0103] Sa4: In step Sa3, if the optimal state of combining performance cannot meet the design requirements, it is necessary to increase the number of serial digital switch lines, or use serial-parallel digital switch lines (that is, each serial digital switch line is changed to a parallel structure, such as Figure 4 As shown), repeat steps Sa2 and Sa3;

[0104] Sa5: traverse all the combined working frequency combinations, repeat steps Sa3 and Sa4, and obtain Table 4;

[0105] Sa6: Write the optimal series (or series-parallel) digital switch line control code corresponding to all the combined frequency combinations obtained above into the EEPROM module 6 on the control board 1;

[0106] Specifically, in steps Sh2 to Sh4 and Sa5, when manually or automatically measuring (or simulating) the combination of two frequency hopping filters, it is necessary to ensure that the frequency interval between the two frequency hopping filters is greater than or equal to 10%; in the manual design step Sh5, in order to facilitate the observation of the transmission line length transformation law, the transmission line length data in Table 1 can be plotted into a curve, and the discrete data samples should be increased in the dense area of ​​the curve, and vice versa; generally, the discrete data is 5 or more samples, and it is necessary to measure or simulate the data with large discrete errors. If the index requirements are not met, the discrete data samples need to be increased; in the automatic design step Sa2, the series (or series-parallel) digital switch line design designs the transmission line length of each bit according to the arithmetic progression. For example, when designing a four-bit series digital switch line, the corresponding transmission line lengths of the four bits are designed to be x, 2x, 3x and 4x, respectively, then 10x=l max; After the above x is obtained, the transmission line length of the lowest bit of the series digital switch line is obtained. If x is larger than the minimum transmission line length in step Sa1, the error is large and the required minimum transmission line length cannot be combined. Generally, it is necessary to increase the number of bits of the series digital switch line, or use a series-parallel digital switch line;

[0107] Among them, the digital switch line is generally a coaxial line, a microstrip line or other common transmission line forms; the length of the transmission line is related to the dielectric constant of the transmission line, and the dielectric constant of the transmission line used in simulation and testing should be consistent with the actual product; since the frequency hopping filter and the parallel digital switch line need to be connected by a transmission line (assuming that the length of this transmission line is L, and there are 5 discrete data), the lengths of the 5 transmission lines in the parallel switch line are 1000-L, 800-L, 600-L, 400-L, and 200-L respectively;

[0108] Specifically, each bit of the serial digital switch line has two working states. When the control bit is "1", the transmission line of this bit is connected, and when the control bit is "0", the transmission line of this bit is "short-circuited" (i.e., the second multidirectional switch 15 selects Figure 3 The first short-circuit wire 16); the selection of the series-parallel digital switch line is similar to the series digital switch line. In order to indicate the state of the entire series-parallel digital switch line, a control bit needs to be added;

[0109] Since the frequency hopping filter and the parallel digital switch line need to be connected by a transmission line (assuming that the length of the transmission line is L and there are 5 discrete data), the actual length of the transmission line connected to each bit in the designed series (or series-parallel) digital switch should be reduced by L, and the actual design of the short-circuit wire in each digital switch line should be one point (that is, the front and rear switches are short-circuited between here, and the short-circuit wire length is 0); Fig.10 and Fig.11 As shown, the use of a transmitting or rotary digital switch line architecture can minimize the length of the short wire.

[0110] by Figure 3 Taking the four-bit serial digital switch line shown in the figure as an example, let the length of the smallest one-bit transmission line be x. According to the arithmetic progression design principle, the lengths of the other three-bit transmission lines are 2x, 3x, and 4x respectively.

[0111] x+2x+3x+4x=l max

[0112] According to l max=968mm≈1000mm, and x=100 is obtained, that is, the transmission line length of each bit of the four-bit series digital switch line is 100mm, 200mm, 300mm, and 400mm, and all combinations with a step of 100mm from 100mm to 1000mm can be combined. Obviously, the series digital switch has higher accuracy than the parallel switch, and the combination matching degree can be better. If the obtained x is larger than the minimum data in Table 2, it is necessary to increase the number of bits of the series digital switch line, or use a series-parallel digital switch line to improve the combination effect.

[0113] A five-bit serial digital switch line is used, and the length of each bit transmission line is x, 2x, 3x, 4x, 5x.

[0114] x+2x+3x+4x+5x=l max

[0115] Similarly, we can get x=67, which shows that a shorter transmission line can be combined to meet the combining requirements;

[0116] use Figure 4 The series-parallel digital switch line shown in the figure can design the first digital switch line to be 100mm and 25mm, the second digital switch line to be 200mm and 75mm, the third digital switch line to be 300mm and 50mm, and the fourth digital switch line to be 400mm and 25mm; in this case, the minimum transmission line length can be 25mm and the step accuracy can be 25mm. The realized digital switch line combination data is highly consistent with Table 2, and the optimal combining effect of each frequency combination is achieved;

[0117] After designing the series (or series-parallel) digital switch line, you can use the automatic tooling to control the series (or series-parallel) digital switch line, traverse all transmission line combinations under each frequency combination, and select the series (or series-parallel) digital switch line working state corresponding to the optimal test result according to the design indicators (select insertion loss, standing wave, combined isolation, etc.), and record the control bit corresponding to this state, such as Figure 7 When the test is completed, the control bits similar to those in Table 4 can be obtained. All the obtained control bits are written into the EEPROM module 6 on the control board 1;

[0118] The above two methods have their own characteristics: the parallel switch line in manual design has low insertion loss and simple design, but it will introduce errors when approximating the line length; the series (or series-parallel) digital switch line used in automatic design has high accuracy, but the insertion loss increases due to the series connection method; in actual use, the most appropriate design method should be selected according to needs;

[0119] like Fig.13 As shown, the present invention also provides a combining method based on a frequency hopping filter, comprising the following steps:

[0120] Get the working frequency data of external radio stations;

[0121] Control the corresponding frequency hopping filter to perform frequency hopping according to the operating frequency data;

[0122] Determine whether there is a control code corresponding to the operating frequency data in the control code data;

[0123] If it exists, the corresponding digital switch line module is controlled according to the control code; if it does not exist, the corresponding control code is determined based on the proximity principle and the corresponding digital switch line module is controlled.

[0124] The working principle and beneficial effects of the above technical solution: when the combiner is working, the control board 1 adjusts the working frequencies of the two RF channels according to the working frequencies of the external radio station 1 and the external radio station 2, so that the two RF channels can be combined, and finally the purpose of sharing the antenna is achieved; the control board, the frequency hopping filter and the digital switch line are all powered by the power board through the adapter board; the control board controls the RF channel, including controlling the frequency hopping filter and the digital switch line;

[0125] The control code data in the EEPROM module 6 is the control code of the digital switch line designed in the early stage; the external radio working frequency, the control code and the transmission line length of the digital switch line correspond to each other, and the radio working frequency is determined, and a set of suitable combined transmission lines can be obtained to realize the combination of the two frequency hopping filters;

[0126] The radio operating frequency should be consistent with the frequency of the frequency hopping filter. When the radio operating frequency is inconsistent with the frequency corresponding to the control code in the EEPROM, the digital switch line control code corresponding to the nearest frequency is taken for control according to the principle of proximity.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A combining system based on a frequency hopping filter, characterized in that: include: A control board (1), an adapter board (2) and a plurality of radio frequency channels, wherein the plurality of radio frequency channels are connected in parallel, and the radio frequency channels include: a frequency hopping filter (3) and a digital switch line module (5), wherein a first port of the frequency hopping filter (3) is connected to an external radio station, a second port of the frequency hopping filter (3) is connected to a first port of the digital switch line module (5), and a second port of the digital switch line module (5) is connected to an external antenna; wherein the frequency hopping filter is used to track the data jump of the working frequency of the external radio station; The control board (1) is provided with an EEPROM module (6) for storing control codes; The control end of the frequency hopping filter (3), the control end of the digital switch line module (5) and the control board (1) are all connected to the adapter board (2) and are used to retrieve the control code through the control board according to the working frequency data of the external radio station to control the digital switch line module to realize the combination of several radio frequency channels.

2. A frequency hopping filter-based combining system as claimed in claim 1, characterized in that: It also includes a power supply board (4), which is connected to the control board (2) and is used to supply power to the system.

3. A frequency hopping filter-based combining system as claimed in claim 1, characterized in that: The digital switch line module (5) is any one of a parallel digital switch line, a series digital switch line and a series-parallel digital switch line.

4. A frequency hopping filter-based combining system as claimed in claim 3, characterized in that: The parallel digital switch line includes: A first line board (13), a first multidirectional switch (7), a first parallel line (8), a second parallel line (9), a third parallel line (10), a fourth parallel line (11) and a fifth parallel line (12); the first line board (13) is provided with the first parallel line (8), the second parallel line (9), the third parallel line (10), the fourth parallel line (11) and the fifth parallel line (12) in parallel; the lengths of the first parallel line (8), the second parallel line (9), the third parallel line (10), the fourth parallel line (11) and the fifth parallel line (12) increase in sequence according to an arithmetic progression; Two first multidirectional switches (7) are symmetrically arranged on the first line board (13), one of the first multidirectional switches (7) is connected to the frequency hopping filter (3), and the other first multidirectional switch (7) is connected to the external antenna. The first multidirectional switch (7) is used to select and connect the corresponding parallel line.

5. A frequency hopping filter-based combining system as claimed in claim 3, characterized in that: The series digital switch line includes: A second line board (14), a second multidirectional switch (15), a first short-circuit wire (16), a first series line (17), a second series line (18), a third series line (19) and a fourth series line (20), wherein four second line boards (14) are arranged side by side, each of the four second line boards (14) is provided with a first short-circuit wire (16) and two second multidirectional switches (15), and two adjacent second line boards (14) are connected via fixed ends of the second directional switches (15) thereon; A first short-circuit wire (16), a first series wire (17), a second series wire (18), a third series wire (19) and a fourth series wire (20) are respectively arranged on four second wire plates (14) in sequence, and the lengths of the first short-circuit wire (16), the first series wire (17), the second series wire (18), the third series wire (19) and the fourth series wire (20) are increased in sequence according to an arithmetic progression.

6. A frequency hopping filter-based combining system as claimed in claim 3, characterized in that: The series-parallel digital switch line includes: A third line board (22), a third multidirectional switch (21), a second short-circuit wire (23), a first series parallel wire (24), a second series parallel wire (25), a third series parallel wire (26) and a fourth series parallel wire (27), four third line boards (22) are arranged side by side, the four third line boards (22) are each provided with a second short-circuit wire (23) and two third multidirectional switches (21), and two adjacent third line boards (22) are connected via fixed ends of the third directional switches (21) thereon; Two first series parallel wires (24), two second series parallel wires (25), two third series parallel wires (26) and two fourth series parallel wires (27) are respectively arranged on four third line boards (22) in sequence, and the lengths of the first series parallel wires (24), the second series parallel wires (25), the third series parallel wires (26) and the fourth series parallel wires (27) increase in sequence according to an arithmetic progression.

7. A frequency hopping filter-based combining system as claimed in claim 6, characterized in that: The first parallel line (8), the second parallel line (9), the third parallel line (10), the fourth parallel line (11), the fifth parallel line (12), the first series line (17), the second series line (18), the third series line (19), the fourth series line (20), the first series parallel line (24), the second series parallel line (25), the third series parallel line (26) and the fourth series parallel line (27) are all digital switch lines.

8. A frequency hopping filter-based combining system as claimed in claim 6, characterized in that: The control ports of the first multidirectional switch (7), the second multidirectional switch (15) and the third multidirectional switch (21) are all connected to the adapter board (2).

9. A combining method based on a frequency hopping filter, characterized in that: The following steps are involved: Get the working frequency data of external radio stations; Control the corresponding frequency hopping filter to perform frequency hopping according to the operating frequency data; Determine whether there is a control code corresponding to the operating frequency data in the control code data; If it exists, the corresponding digital switch line module is controlled according to the control code; if it does not exist, the corresponding control code is determined based on the proximity principle and the corresponding digital switch line module is controlled.

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