A solid state low frequency transmitter matching filter circuit

Abstract

The application discloses a kind of solid-state low-frequency signaling machine matching filter circuit, comprising: first intermediate slot, Butterworth filter and second intermediate slot are electrically connected in sequence;Butterworth filter is used for impedance matching and inhibiting high harmonic component;First, second intermediate slot each includes capacitor frame group and adjustable inductance coil group in series with each other;Capacitor frame group and adjustable inductance coil group are connected with corresponding capacitor or inductance into matching filter main loop as needed by the setting of switch switch.The application especially increases the first intermediate slot, can adjust the impedance characteristic of signaling main machine access loop to make access impedance approximately reach pure resistance state, reduce the voltage and current transient impact that power device of solid-state signaling machine is subjected to when working;By closing and opening operation of switch switch, the working frequency band segmentation tuning of solid-state low-frequency signaling machine can be realized;Therefore it has the characteristics of access impedance matching and segmented tuning simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication electronics, more particularly, to a solid-state low-frequency transmitter matching filter circuit. BACKGROUND

[0002] Low-frequency communication refers to a communication mode using radio waves for long-distance signal transmission. The low-frequency transmitter matching filter circuit is designed according to the characteristics of the electronic tube transmitter, which uses more switching switches, increasing the complexity of the control system.

[0003] The solid-state transmitter power amplifier circuit is composed of high-power-density power electronic devices, which are different from electronic tubes or hydrogen-filled thyristors. These devices are more sensitive to the circuit characteristics of the connected load in the loop. When the connected circuit presents strong inductance or capacitance, it will cause high voltage spikes or large transient pulse currents during the turn-on or turn-off process of the power device, and also increase the high-order harmonic content in the power amplifier loop. Therefore, the circuit characteristics after the transmitter host have a great influence on the power amplifier loop, which may shorten the service life or even damage the device. If the aforementioned matching filter circuit suitable for electronic tube transmitters is directly used, the solid-state transmitter output is directly connected to the filter, and the above problems will exist.

[0004] In addition, before the low-frequency transmitter works, it needs to be tuned according to different working frequencies. When the frequency changes, the tuning must be realized by switching. The 3-order π-type filter needs to control the switching operation of at least 12 switching switches, and the 7-order Butterworth filter needs to control the switching operation of more switching switches. Although the tuning control system can automatically execute the switching action according to the tuning operation table during tuning, the switching time required for a series of switching operations is still relatively long. SUMMARY

[0005] In view of at least one defect or improvement demand of the prior art mentioned in the background art part, the present application provides a solid-state low-frequency transmitter matching filter circuit, wherein by designing the structure of the key components and the circuit connection mode thereof, the complexity of the control system can be greatly reduced while achieving the desired matching filter effect, and the solid-state low-frequency transmitter matching filter circuit has the characteristics of compact structure, easy operation, and meeting the working requirements of high-power solid-state low-frequency transmitters.

[0006] To achieve the above-mentioned purpose, the present application provides a solid-state low-frequency transmitter matching filter circuit, comprising: a first intermediate tank circuit, a Butterworth filter and a second intermediate tank circuit connected in sequence.

[0007] The Butterworth filter is used for impedance matching and high-order harmonic component suppression.

[0008] The first and second intermediate slots each include a capacitor bank and an adjustable inductor coil group connected in series with each other.

[0009] The capacitor bank is composed of a main capacitor bank with relatively large overall capacitance value and several additional capacitor banks with relatively small overall capacitance value, and the main capacitor bank is always connected in series to the matching filter main loop, while the additional capacitor banks are connected in parallel to the main capacitor bank via corresponding switching switches to the matching filter main loop; the first intermediate slot is connected to an external signaling host through the access point of its capacitor bank.

[0010] The adjustable inductor coil group is composed of several adjustable inductor coils connected in series to the matching filter main loop, and the connections between the adjustable inductor coils of the first intermediate slot are connected to the access point of the Butterworth filter via switching switches, while the connections between the adjustable inductor coils of the second intermediate slot are connected to the access point of the external later-stage coupling circuit via switching switches.

[0011] Further, the capacitor bank of the first intermediate slot is composed of a main capacitor bank with relatively large overall capacitance value and an additional capacitor bank with relatively small overall capacitance value; the adjustable inductor coil group of the first intermediate slot is composed of two adjustable inductor coils connected in series to the matching filter main loop.

[0012] Further, the capacitor bank of the second intermediate slot is composed of a main capacitor bank with relatively large overall capacitance value and an additional capacitor bank with relatively small overall capacitance value; the adjustable inductor coil group of the second intermediate slot is composed of three adjustable inductor coils connected in series to the matching filter main loop.

[0013] Further, the main capacitor bank and the additional capacitor bank each include a plurality of capacitor groups arranged in series on a busbar, and each capacitor group is composed of a plurality of capacitors connected in parallel with each other.

[0014] Further, the inductance value of each adjustable inductor coil is adjustable within the same range, and the linkage of multiple adjustable inductor coils is controlled by a servo motor.

[0015] Further, the Butterworth filter is composed of several fixed inductor coils and several capacitor banks, the fixed inductor coils are connected in series in the matching filter main loop, and each capacitor bank is composed of a plurality of capacitors arranged in parallel with each other on a busbar; one end of each capacitor bank is connected to the connection between the fixed inductor coils, and the other end of each capacitor bank is grounded.

[0016] Further, the Butterworth filter is composed of four fixed inductance coils and three capacitor racks, wherein the first and fourth fixed inductance coils at two ends have the same inductance value, and the second and third fixed inductance coils in the middle have the same inductance value; for the three capacitor racks, the first and third capacitor racks at two ends have the same total capacitance value, and the second capacitor rack in the middle has a total capacitance value different from that of the other two capacitor racks.

[0017] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0018] (1) The present application combines the working characteristics of a high-power solid-state low-frequency signaling machine to design the specific structure of key components of a matching filter circuit and the circuit connection mode thereof, especially a first intermediate tank circuit is added, which can adjust the impedance characteristics of the signaling host access circuit, so that the access impedance of the signaling host can be approximately in a pure resistive state, reducing the voltage and current transient impact on the power device of the solid-state signaling machine during operation. In addition, it also plays a certain filtering role.

[0019] (2) The present application designs the internal structure of the first and second intermediate tank circuits, especially the setting mode of the switching switch, so that the solid-state low-frequency signaling machine can be segmented tuned in the working frequency band only by closing and opening the first and second intermediate tank circuit switching switches, and the adjustable inductance coils of the first and second intermediate tank circuits can also adjust the inductance values of the first and second fixed inductance coils of the Butterworth filter, so that the Butterworth filter can better play a matching filtering role.

[0020] (3) The present application designs the internal structure of the Butterworth filter, which can save a large number of switching switches, which on the one hand can effectively reduce the complexity of the tuning control system, and on the other hand can shorten the frequency point switching time.

[0021] (4) The overall structure of the matching filter circuit designed by the present application is compact and easy to operate, and has the characteristics of good access impedance matching and segmented tuning. Practice tests show that it can greatly reduce the high harmonic content of the signaling machine output current, has flexible impedance matching characteristics, and can effectively reduce the complexity of the tuning control system, so it is especially suitable for the matching filtering of solid-state low-frequency signaling machines. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below only show some of the embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0023] Figure 1 The overall structure block diagram of the solid-state low-frequency transmitter matching filter circuit provided by the embodiment of the present application is shown in the figure.

[0024] Figure 2 The specific circuit structure diagram of the solid-state low-frequency transmitter matching filter circuit provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0026] The terms "first", "second" or "third" and the like in the specification of the present application, claims or the above drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0027] In one embodiment, the overall structure diagram of the solid-state low-frequency transmitter matching filter circuit designed according to the present application is shown in the figure. Figure 1 The matching filter circuit includes a first intermediate tank circuit, a Butterworth filter and a second intermediate tank circuit connected in sequence. The two ends of the Butterworth filter are connected in series with the first intermediate tank circuit and the second intermediate tank circuit respectively, and the ground end is connected to the ground. One end (shown as the left end in the figure) of the first intermediate tank circuit is connected to the output end of the transmitter host, and the other end (shown as the right end in the figure) is connected to the input end of the Butterworth filter. One end (shown as the left end in the figure) of the second intermediate tank circuit is connected to the output end of the Butterworth filter, and the other end (shown as the right end in the figure) is connected to the input end of the subsequent coupling circuit.

[0028] As shown in the figure, Figure 2As shown, the first and second intermediate tank circuits each include a capacitor bank and an adjustable inductor coil group connected in series with each other, wherein the capacitor bank is composed of a main capacitor bank with relatively large overall capacitance value and one or more additional capacitor banks with relatively small overall capacitance value, and the main capacitor bank is always connected in series in the matching filter main circuit, while the additional capacitor banks are connected in parallel in the matching filter main circuit with the main capacitor bank via corresponding switching switches, so that the additional capacitor banks can be connected in the matching filter main circuit by closing the switching switches; the adjustable inductor coil group is composed of a plurality of adjustable inductor coils connected in series in the matching filter main circuit, and the connections between the adjustable inductor coils of the first intermediate tank circuit are connected to the access point of the Butterworth filter via switching switches, while the connections between the adjustable inductor coils of the second intermediate tank circuit are connected to the access point of the later-stage coupling circuit via switching switches, so that part of the adjustable inductor coils therein can be short-circuited from the matching filter main circuit by closing the switching switches.

[0029] Referring to Figure 2 , a schematic diagram of the circuit structure of the matching filter circuit of the preferred embodiment of the present application is exemplarily shown. As Figure 2 shown, the matching filter circuit includes a first intermediate tank circuit, a Butterworth filter and a second intermediate tank circuit connected in series. For the first intermediate tank circuit, its capacitor bank is composed of a main capacitor bank C11 with relatively large overall capacitance value and an additional capacitor bank C12 with relatively small overall capacitance value, and the main capacitor bank C11 is always connected in series in the matching filter main circuit, while the additional capacitor bank C12 is connected in parallel in the matching filter main circuit with the main capacitor bank C11 via a corresponding switching switch K11; its adjustable inductor coil group is composed of two adjustable inductor coils L11 and L12 connected in series in the matching filter main circuit, and the middle connection of the two adjustable inductor coils is connected to the access point of the Butterworth filter via a switching switch K12.

[0030] For the second intermediate tank circuit, its capacitor bank is composed of a main capacitor bank C31 with relatively large overall capacitance value and an additional capacitor bank C32 with relatively small overall capacitance value, and the main capacitor bank C31 is always connected in series in the matching filter main circuit, while the additional capacitor bank C32 is connected in parallel in the matching filter main circuit with the main capacitor bank C31 via a corresponding switching switch K31; its adjustable inductor coil group is composed of three adjustable inductor coils L31, L32 and L33 connected in series in the matching filter main circuit, and the connections between the three adjustable inductor coils are respectively connected to the access point of the later-stage coupling circuit via switching switches K32 and K33.

[0031] For the Butterworth filter, it is composed of four fixed inductors L21, L22, L23 and L24 and three capacitor racks C21, C22 and C23, wherein the first fixed inductor L21 at both ends has the same inductance value as the fourth fixed inductor L24, and the second fixed inductor L22 and the third fixed inductor L23 in the middle have the same inductance value; for the above-mentioned three capacitor racks, the first capacitor rack C21 and the third capacitor rack C23 at both ends have the same total capacitance value, and the second capacitor rack C22 arranged in the middle has a total capacitance value different from that of C21 or C23.

[0032] According to a preferred embodiment of the present application, for the main capacitor rack and the additional capacitor rack of the first and second intermediate slot, each of them comprises a plurality of capacitor groups arranged in series on the busbar, and each capacitor group is composed of a plurality of capacitors in parallel with each other; in addition, the capacitor rack as a whole is fixed to the ground by an insulating support, while preventing the internal capacitors from discharging to the ground. In addition, for the plurality of adjustable inductors of the adjustable inductor group of the first and second intermediate slot, the adjustable range of the inductance value of each of them is the same as each other, and the plurality of inductors are controlled in linkage by a servo motor, thereby realizing the adjustment of the inductance value of the inductor.

[0033] According to another preferred embodiment of the present application, the Butterworth filter is composed of a plurality of fixed inductors and a plurality of capacitor racks, wherein the plurality of fixed inductors are connected in series with each other in the matching filter main loop, each of the capacitor racks is composed of a plurality of capacitors arranged in parallel with each other on the busbar, and one end of the overall structure of each capacitor rack is connected to the connection between the plurality of fixed inductors, and the other end of the overall structure of each capacitor rack is grounded. In addition, as a further preferred embodiment, the Butterworth filter is composed of four fixed inductors and three capacitor racks, wherein the first fixed inductor at both ends has the same inductance value as the fourth fixed inductor, and the second fixed inductor and the third fixed inductor in the middle have the same inductance value; for the above-mentioned three capacitor racks, the first capacitor rack and the third capacitor rack have the same total capacitance value, and the second capacitor rack has a total capacitance value different from that of the first capacitor rack and the third capacitor rack.

[0034] The concept and related technical effects of the present application will be further explained in detail below.

[0035] By adding an intermediate slot and the first and second intermediate slot capacitor frame group is designed as above-mentioned segment adjustable, and the overall relatively large capacitance value of the main capacitor frame is always connected in series in the matching filter main circuit, and the overall relatively small capacitance value of the additional capacitor frame is connected in parallel with the main capacitor frame via the corresponding switching switch and connected into the matching filter main circuit, in this way, the additional capacitor frame can be disconnected from the matching filter main circuit by breaking the switching switch. At the same time, by designing the inductor coil group of the first and second intermediate slot as above-mentioned continuous adjustable, and the connection between these adjustable inductor coils is connected to the access point of the Butterworth filter or the later stage coupling circuit via the corresponding switching switch, in this way, by closing the switching switch, part of the adjustable inductor coils can be short-circuited from the matching filter main circuit.

[0036] According to the above design, the capacitor frame group and the adjustable inductor coil group form a series resonance circuit, and the frequency is segmented by the number of capacitor frames connected into the matching filter main circuit, and the series resonance is realized by changing the inductance value of the adjustable inductor coil group. The corresponding first intermediate slot can make the access impedance of the signaling host approximately pure resistance, thereby reducing the influence of the access circuit on the signaling host power amplifier circuit, and the second intermediate slot can make the access impedance of the circuit after the Butterworth filter approximately pure resistance, thereby reducing the influence of the primary self-inductance of the coupling circuit on the resonated previous stage circuit. In particular, the first and second intermediate slots can themselves play a certain role in suppressing harmonics, and their adjustable inductor coils can also play a role in adjusting the inductance values of the first and last fixed inductor coils of the Butterworth filter, thereby making the Butterworth filter better play the role of matching filtering.

[0037] By composing the Butterworth filter with multiple fixed inductor coils and multiple capacitor frames, and connecting the multiple fixed inductor coils in series in the matching filter main circuit, and composing the capacitor frame with multiple capacitors arranged in parallel on the busbar, and connecting one end of each capacitor frame to the connection between the multiple fixed inductor coils, and connecting the other end of each capacitor frame to the ground.

[0038] According to the above design, the Butterworth filter composed of fixed capacitors and fixed inductor coils can suppress the high harmonic components of the signaling host output current, and realize impedance matching between the signaling host and the later stage circuit. At the same time, a large number of switching switches can be omitted, which can effectively reduce the complexity of the tuning control system and shorten the frequency point switching time.

[0039] In actual application, for example, for Figure 2In the embodiment shown in the middle, the number of capacitor racks selected in a frequency band range is fixed, and the rotation of the adjustable inductance coil controlled by the servo motor is used to realize the continuous adjustment of the inductance value, so that the tuning operation of the first intermediate slot circuit at any frequency point in the frequency band can be realized. For example, the center frequency angular frequency of the first frequency band of the first intermediate slot circuit is ω, in order to ensure that the actual Q value meets the engineering experience value, the Q value at the center frequency point is selected as 6, and the characteristic impedance is 10Ω. According to the formula C=1 / ωRQ, the required capacitance value of the first frequency band can be calculated, and the required inductance range of the first frequency band can be calculated through the formula L=1 / ω 2 C. The required capacitance value of the second frequency band and the required inductance range can be calculated in the same way. The capacitance value of the main capacitor rack is the required capacitance value of the second frequency band, and the capacitance value of the additional capacitor rack is the difference between the required capacitance values of the first and second frequency bands. In order to facilitate the linkage tuning operation of the adjustable inductance coil by the servo motor, the two adjustable inductance coils of the adjustable inductance coil group are designed to be the same, and the use of the adjustable inductance coil group in cooperation with the switching switch can provide that the lower limit of the inductance value range is not greater than the minimum value of the required inductance of the two frequency bands, and the upper limit is not less than the maximum value of the required inductance of the two frequency bands.

[0040] The second intermediate slot circuit is also designed according to the two frequency bands described above, except that the inductance adjustment range needs to be larger because the second intermediate slot circuit is connected to the coupling circuit, so the adjustable inductance coil group selects three adjustable inductance coils, and the Q value at the center frequency point is selected as 7 during calculation. The electrical parameter calculation method is consistent with that of the first intermediate slot circuit.

[0041] In addition, as known from the typical Butterworth filter structure, the inductance values of the fixed inductance coils L21 and L24 of the Butterworth filter can be the same, the inductance values of the fixed inductance coils L22 and L23 can be the same, and the capacitance values of the fixed capacitor racks C21 and C23 are the same. According to the required cutoff frequency and characteristic impedance value, the above-mentioned capacitance value and inductance value can be calculated. In particular, in order to maintain design consistency, the structures of the required three fixed capacitor racks can be kept the same, and only the fixed capacitor rack C21 needs to be installed with more capacitors than the other two capacitor racks.

[0042] The above-described embodiments are merely exemplary and do not limit the scope of the disclosure. Any equivalent changes or modifications to the above-described embodiments that are made in light of the teachings of the disclosure should fall within the scope of the disclosure. Other implementations of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the disclosure being indicated by the following claims.

[0043] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described, however, any combination of the technical features is considered to be within the scope of the disclosure.

[0044] Those skilled in the art easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should fall within the protection scope of the present application.

Claims

1. A solid state low frequency transmitter matching filter circuit, comprising: The utility model relates to a kind of matching filter, including: First intermediate slot, Butterworth filter and second intermediate slot connected in turn are electrically connected; The Butterworth filter is used for impedance matching and inhibiting high harmonic component;The Butterworth filter is composed of several fixed inductance coils and several capacitors, several fixed inductance coils are connected in series in the matching filter main circuit, each capacitor rack is composed of multiple capacitors arranged in parallel on busbar;One end of each capacitor rack structure is connected to the connection between several fixed inductance coils, and the other end of each capacitor rack structure is grounded respectively; The first and second intermediate slot each include capacitor rack group and adjustable inductance coil group connected in series with each other; The capacitor rack group is composed of one main capacitor rack with relatively large overall capacitance value and several additional capacitor racks with relatively small overall capacitance value, and each of the main capacitor rack and the additional capacitor rack includes multiple capacitor groups arranged in series on busbar, and each capacitor group is composed of multiple capacitors connected in parallel with each other;And the main capacitor rack is always connected in series in the matching filter main circuit, and the additional capacitor rack is connected in parallel with the main capacitor rack in the matching filter main circuit via corresponding switching switch;The first intermediate slot is connected to external signaling host through the access point of its capacitor rack group; The adjustable inductance coil group is composed of several adjustable inductance coils connected in series in the matching filter main circuit, and the connection between the adjustable inductance coils of the first intermediate slot is connected to the access point of the Butterworth filter via switching switch, and the connection between the adjustable inductance coils of the second intermediate slot is connected to the access point of external rear-stage coupling circuit via switching switch.

2. The matched filter circuit of claim 1, wherein, The capacitor rack group of the first intermediate slot is composed of one main capacitor rack with relatively large overall capacitance value and one additional capacitor rack with relatively small overall capacitance value;The adjustable inductance coil group of the first intermediate slot is composed of two adjustable inductance coils connected in series in the matching filter main circuit.

3. The matched filter circuit of claim 1, wherein, The capacitor rack group of the second intermediate slot is composed of one main capacitor rack with relatively large overall capacitance value and one additional capacitor rack with relatively small overall capacitance value;The adjustable inductance coil group of the second intermediate slot is composed of three adjustable inductance coils connected in series in the matching filter main circuit.

4. A matched filter circuit as claimed in any one of claims 1 to 3, characterized in that, The inductance value of each adjustable inductance coil is adjustable in the same range, and the linkage of multiple adjustable inductance coils is controlled by servo motor.

5. The matched filter circuit of claim 1, wherein, The Butterworth filter is composed of four fixed inductance coils and three capacitor racks, wherein the inductance values of the first and fourth fixed inductance coils at both ends are the same, and the inductance values of the second and third fixed inductance coils in the middle are the same;For the above three capacitor racks, the overall capacitance values of the first and third capacitor racks at both ends are the same, and the overall capacitance value of the second capacitor rack in the middle is different from the overall capacitance values of the other two capacitor racks.

Images