CN210016446U - Front-end filter circuit of long-wave receiver - Google Patents
Front-end filter circuit of long-wave receiver Download PDFInfo
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- CN210016446U CN210016446U CN201920703817.3U CN201920703817U CN210016446U CN 210016446 U CN210016446 U CN 210016446U CN 201920703817 U CN201920703817 U CN 201920703817U CN 210016446 U CN210016446 U CN 210016446U
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- filter circuit
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Abstract
The utility model relates to a long wave receiver front end filter circuit, the circuit includes: the filter comprises a first filter circuit, a second filter circuit, a third filter circuit, a gain control circuit and a gain adjusting circuit, wherein the input end of the first filter circuit is connected with the input end of a long wave signal, the first filter circuit, the second filter circuit and the third filter circuit are sequentially connected, the output end of the third filter circuit is connected with the input end of the gain control circuit and the input end of the gain adjusting circuit, the output end of the gain control circuit is connected with the input end of the gain adjusting circuit, and the output end of the gain adjusting circuit is connected with the output end of the long wave signal. The utility model provides a filter circuit is active filter circuit, circuit structure is simple, and the volume is less.
Description
Technical Field
The utility model belongs to the technical field of long wave navigation receiver, concretely relates to long wave receiver front end filter circuit.
Background
With the development of society and the advance of science and technology, the long wave navigation receiver has very important significance for radio navigation.
In the long wave system, a receiver receives a long wave signal of a ground station for navigation calculation, and the receiver mainly comprises front-end filtering signal amplification and baseband signal processing navigation calculation. The long-wave signal has the advantages of longer wavelength, stronger diffraction capability and the like, so that the ground remote navigation system is widely used.
However, for long-wavelength systems, the filter design of the front end of the receiver is due to the wavelength problem, and the filter designed by the traditional filter design technology is large in size.
SUMMERY OF THE UTILITY MODEL
In order to solve the deficiencies in the prior art, the utility model provides a long wave receiver front end filter circuit, this circuit includes:
a first filter circuit, a second filter circuit, a third filter circuit, a gain control circuit, and a gain adjustment circuit,
the input end of the first filter circuit is connected with the long wave signal input end, the first filter circuit, the second filter circuit and the third filter circuit are sequentially connected, the output end of the third filter circuit is connected with the input end of the gain control circuit and the input end of the gain adjusting circuit, the output end of the gain control circuit is connected with the input end of the gain adjusting circuit, and the output end of the gain adjusting circuit is connected with the long wave signal output end.
In one embodiment of the present invention, the first filter circuit comprises operational amplifier a1, operational amplifier a2, and operational amplifier A3, wherein,
an inverting input terminal of the operational amplifier a1 is connected to the long-wave signal input terminal, an output terminal of the operational amplifier a1 is connected to an inverting input terminal of the operational amplifier a2, an output terminal of the operational amplifier a2 is connected to the inverting input terminal of the operational amplifier A3 and the input terminal of the second filter circuit, an output terminal of the operational amplifier A3 is connected to the inverting input terminal of the operational amplifier a1, and a non-inverting input terminal of the operational amplifier a1, a non-inverting input terminal of the operational amplifier a2 and a non-inverting input terminal of the operational amplifier A3 are all grounded.
In one embodiment of the present invention, the second filter circuit comprises operational amplifier a4, operational amplifier a5, and operational amplifier a6, wherein,
an inverting input terminal of the operational amplifier a4 is connected to an output terminal of the operational amplifier a2 and an inverting input terminal of the operational amplifier A3, an output terminal of the operational amplifier a4 is connected to an inverting input terminal of the operational amplifier a5, an output terminal of the operational amplifier a5 is connected to the third filter circuit input terminal and an inverting input terminal of the operational amplifier A6, an output terminal of the operational amplifier A6 is connected to an inverting input terminal of the operational amplifier a4, and a non-inverting input terminal of the operational amplifier a4, a non-inverting input terminal of the operational amplifier a5, and a non-inverting input terminal of the operational amplifier A6 are all grounded.
In one embodiment of the present invention, the third filter circuit comprises operational amplifier a7, operational amplifier A8, and operational amplifier a9, wherein,
an inverting input terminal of the operational amplifier a7 is connected to an output terminal of the operational amplifier a5 and an inverting input terminal of the operational amplifier A6, an output terminal of the operational amplifier a7 is connected to an inverting input terminal of the operational amplifier A8, an output terminal of the operational amplifier A8 is connected to the gain control circuit, the gain adjustment circuit, and an inverting input terminal of the operational amplifier a9, an output terminal of the operational amplifier a9 is connected to an inverting input terminal of the operational amplifier a7, and a non-inverting input terminal of the operational amplifier a7, a non-inverting input terminal of the operational amplifier A8, and a non-inverting input terminal of the operational amplifier a9 are all grounded.
In an embodiment of the present invention, the models of the operational amplifier a1, the operational amplifier a2, the operational amplifier A3, the operational amplifier a4, the operational amplifier a5, the operational amplifier a6, the operational amplifier a7, the operational amplifier A8, and the operational amplifier a9 are LT 1365.
In an embodiment of the present invention, the gain adjusting circuit is a gain amplifier.
In one embodiment of the present invention, the gain amplifier model is THS7001 IPWP.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the utility model provides a filter circuit is active filter circuit, circuit structure is simple, and the volume is less.
2. The utility model provides a filter circuit has carried out the series connection with tertiary active filter circuit, has improved outband rejection ability, carries out the filtering to outband interference effectively, guarantees that long wave signal phase place does not change, and the phase place keeps good.
3. The utility model provides a filter circuit adopts gain control circuit and gain adjustment circuit to realize that the gain of signal is controllable after the filtering, and control range is 44dB, for receiver baseband processing and navigation are solved and are provided good quality's received signal, lays good foundation for follow-up navigation settlement precision.
4. The filter circuit provided by the embodiment has the advantages of simple circuit design, no need of debugging after the circuit parameter design is completed, high circuit performance consistency and suitability for batch production.
Drawings
Fig. 1 is a schematic structural diagram of a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a first filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a second filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention;
fig. 4 is a schematic circuit diagram of a third filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention.
Description of reference numerals:
a first filter 10; a second filter 20; a third filter 30; a gain control circuit 40; a gain adjustment circuit 50.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the present invention is not limited thereto.
In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention can be embodied in many different forms other than those specifically described herein, and it will be apparent to those skilled in the art that similar modifications can be made without departing from the spirit and scope of the invention, and it is therefore not to be limited to the specific embodiments disclosed below.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Example one
The utility model relates to a long wave receiver front end filter circuit. Referring to fig. 1, fig. 1 is a schematic structural diagram of a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention. Specifically, the utility model provides a long wave receiver front end filter circuit includes:
a first filter circuit 10, a second filter circuit 20, a third filter circuit 30, a gain control circuit 40, and a gain adjustment circuit 50, wherein,
the input end of the first filter circuit 10 is connected with the input end of a long wave signal, the first filter circuit 10, the second filter circuit 20 and the third filter circuit 30 are sequentially connected, the output end of the third filter circuit 30 is connected with the input end of the gain control circuit 40 and the input end of the gain adjusting circuit 50, the output end of the gain control circuit 40 is connected with the input end of the gain adjusting circuit 50, and the output end of the gain adjusting circuit 50 is connected with the output end of the long wave signal.
Specifically, in a long wave system, a receiver receives a long wave signal of a ground station for navigation calculation, and the receiver mainly comprises front-end filtering signal amplification and baseband signal processing navigation calculation. In the traditional filter design, due to the wavelength problem of a front-end filter of the receiver, the designed filter is large in size, and phase delay cannot be determined under different signal amplitudes, so that the navigation resolving result is large in error under different use conditions, and the baseband resolving design difficulty of the receiver is increased.
In view of the above, the present embodiment provides a long wave receiver front end filter, wherein,
and the first filter circuit 10 is connected with the long-wave signal input end and is used for filtering the long-wave signal to obtain a first filter signal.
Specifically, please refer to fig. 2, fig. 2 is a schematic circuit diagram of a first filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention. It can be seen that the first filter circuit 10 of the present embodiment includes an operational amplifier a1, an operational amplifier a2, and an operational amplifier A3. The specific connections of the operational amplifier a1, the operational amplifier a2, and the operational amplifier A3 in the first filter circuit 10 have been described in detail above, and will not be described in detail here. In this embodiment, the operational amplifier a1 realizes a low-pass filter function, the cutoff frequency is 70KHz, the operational amplifier a2 realizes a high-pass filter function, the cutoff frequency is 120KHz, the operational amplifier a1 and the operational amplifier a2 jointly realize a band-pass filter function, phase-lossless band-pass filtering is performed, and the frequency range of the filtering is 70KHz to 120 KHz; the operational amplifier A3 realizes negative feedback function, so that the loop of the band-pass filter composed of the operational amplifier A1 and the operational amplifier A2 works at a stable static working point.
Preferably, operational amplifier A1, operational amplifier A2, and operational amplifier A3 are all LT1365 in model number.
Further, the second filter circuit 20 is connected to the first filter circuit 10, and is configured to perform filtering processing on the first filtered signal to obtain a second filtered signal.
Specifically, please refer to fig. 3, fig. 3 is a schematic circuit diagram of a second filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention. The second filter circuit 20 of the present embodiment includes an operational amplifier a4, an operational amplifier a5, and an operational amplifier a 6. The connection relationship of the operational amplifier a4, the operational amplifier a5, and the operational amplifier a6 in the second filter circuit 20 has been described in detail as above, and will not be described in detail herein. The specific functions of the operational amplifier a4, the operational amplifier a5 and the operational amplifier a6 are implemented as the operational amplifier a1, the operational amplifier a2 and the operational amplifier A3 in the first filter circuit 10, and will not be described in detail herein.
Preferably, operational amplifier A4, operational amplifier A5, and operational amplifier A6 are all LT1365 in model number.
Further, the third filter circuit 30 is connected to the second filter circuit 20, and is configured to perform filtering processing on the second filtered signal to obtain a third filtered signal.
Specifically, please refer to fig. 4, fig. 4 is a schematic circuit diagram of a third filter circuit in a front-end filter circuit of a long-wavelength receiver according to an embodiment of the present invention. The third filter circuit 30 of the present embodiment includes an operational amplifier a7, an operational amplifier A8, and an operational amplifier a 9. The connection relationship of the operational amplifier a7, the operational amplifier A8, and the operational amplifier a9 in the third filter circuit 30 has been described in detail as above, and will not be described in detail here. The specific functions of the operational amplifier a7, the operational amplifier A8, and the operational amplifier a9 of the third filter circuit 30 are implemented as the operational amplifier a1, the operational amplifier a2, and the operational amplifier A3 of the first filter circuit 10, and the operational amplifier a4, the operational amplifier a5, and the operational amplifier a6 of the second filter circuit 20, which will not be described in detail herein.
Preferably, operational amplifier A7, operational amplifier A8, and operational amplifier A9 are all LT1365 in model number.
In the embodiment, through the series connection of the three-level active filter circuit of the first filter circuit 10, the second filter circuit 20 and the third filter circuit 30, the broadband response characteristic of a low-noise operational amplifier is adopted, a basic model of an infinite gain active filter is designed, and a negative feedback circuit is utilized, so that the filtering is realized while no influence is generated on an in-band signal, the out-band rejection capability of a front-end filter of a long-wave receiver is improved, out-band interference is effectively filtered, the phase of the long-wave signal is ensured not to change, and the phase is kept well.
Further, the gain control circuit 40 is connected to the third filter circuit 30, and is configured to obtain the gain control signal according to the third filtered signal.
Specifically, referring to fig. 1 and fig. 4 again, the input terminal of the gain control circuit 40 of the present embodiment is connected to the output terminal of the operational amplifier A8 and the inverting input terminal of the operational amplifier a9 in the third filter circuit 30, and the output terminal of the gain control circuit 40 is connected to the input terminal of the gain adjustment circuit. In this embodiment, the gain control circuit 40 uses a three-bit binary gain control signal, so as to implement a gain control range of 44dB for 8 levels of the third filtering signal. The control of gain by a specific three-bit binary gain control signal is shown in table 1.
TABLE 1 control of gain by three-bit binary
As can be seen from Table 1, the gain control ranges from-22 dB to 20dB, and the gain control is divided into 8-level control. In this embodiment, the generation of the ternary binary gain control signal may be that the gain control circuit 40 performs the judgment of the signal being too large or too small through a preset signal range pre-stored in the third filtering signal itself, outputs the gain control signal to the gain adjustment circuit 50, and amplifies or reduces the gain of the third filtering signal according to the gain control signal shown in table 1, or may also perform the amplification or reduction of the gain by using the baseband to determine whether the current third filtering signal meets the requirement of the baseband, and provides the gain control signal shown in table 1 to the gain control circuit 40, and the gain control circuit 40 performs the amplification or reduction of the gain of the third filtering signal by the gain adjustment circuit 50 through the gain control signal.
Further, the gain adjusting circuit 50 is connected to the third filter circuit 30, the gain control circuit 40 and the long-wave signal output end, and is configured to adjust the third filtered signal according to the gain control signal to obtain a long-wave filtered signal, and output the long-wave filtered signal from the long-wave signal output end.
Specifically, referring to fig. 1 and fig. 4 again, the input terminal of the gain adjustment circuit 50 of the present embodiment is connected to the output terminal of the operational amplifier A8 in the third filter circuit 30, the inverting input terminal of the operational amplifier a9, and the output terminal of the gain control circuit 40, and the output terminal of the gain adjustment circuit 50 is connected to the output terminal of the long-wave signal. In this embodiment, the gain adjusting circuit 50 performs the gain adjustment as shown in table 1 on the third filtered signal output by the third filtering circuit 30 according to the three-bit binary gain control signal output by the gain control circuit 40. For example, the gain control signal output by the gain control circuit 40 to the gain adjustment circuit 50 is 010, which means that the gain adjustment circuit 50 needs to perform a gain reduction operation on the third filtered signal, specifically, the gain control signal is reduced by 10 db; the gain control signal output by the gain control circuit 40 to the gain adjustment circuit 50 is 110, which means that the gain adjustment circuit 50 needs to perform a gain amplification operation on the third filtered signal, specifically, the gain amplification is 14 db. And meanwhile, outputting the third filtering signal after the gain adjustment to a baseband from a long wave signal output end, wherein the third filtering signal after the gain adjustment is the long wave filtering signal.
Preferably, the gain adjustment circuit 50 employs a gain amplifier, which is of the type THS7001 IPWP.
In summary, in the present embodiment, the gain control circuit 40 and the gain adjustment circuit 50 are adopted to realize the gain control of the filtered signal, and the gain control range is 44dB, so as to provide a good received signal for the baseband processing and navigation solution of the receiver, and lay a good foundation for the subsequent navigation settlement accuracy.
Further, this embodiment is connected with signal matching circuit between each stage circuit, and signal matching circuit includes signal resistance matching circuit and signal capacitance matching circuit, and wherein, signal resistance matching circuit includes input signal resistance matching circuit and output signal resistance matching circuit, and signal capacitance matching circuit includes input signal capacitance matching circuit and output signal capacitance matching circuit.
Preferably, the input signal matching circuit adopts a first resistor, and the model number of the first resistor is RM 0805-453-J; the output signal matching circuit adopts a second resistor, and the model of the second resistor is RM 0805-472-J; the input signal capacitance matching circuit and the output signal capacitance matching circuit both adopt capacitors, and the model of the capacitor is CCTL 41-CG-102-J.
Specifically, in the present embodiment, input signal resistance matching circuits are connected between the long-wave signal input terminal and the first filter circuit 10, between the first filter circuit 10 and the second filter circuit 20, between the second filter circuit 20 and the third filter circuit 30, and between the third filter circuit 30 and the gain adjustment circuit 50, an output signal resistance matching circuit is connected between the gain adjustment circuit 50 and the long-wave signal output terminal, an input signal capacitance matching circuit is connected between the third filter circuit 30 and the gain control circuit 40, and an output signal capacitance matching circuit is connected between the gain control circuit 40 and the gain adjustment circuit 50. The input signal resistance matching circuit and the output signal resistance matching circuit are used for impedance matching and signal transmission among the circuits, and the input signal capacitance matching circuit and the output signal capacitance matching circuit are used for filtering processing and signal transmission among the circuits. Specifically, for a 1000kHz signal, the values of the capacitors in the input signal capacitance matching circuit and the output signal capacitance matching circuit are both 1000PF, and the selection of the capacitors is determined according to the frequency responses of the capacitors with different capacitance values; in the embodiment, the resistance value of the first resistor of the input signal resistance matching circuit and the resistance value of the second resistor of the output signal resistance matching circuit are determined by the direct current level state among the circuits, and for the first resistor with the model number of RM0805-453-J, the resistance value is 45K ohms, and for the second resistor with the model number of RM0805-472-J, the resistance value is 4.7K ohms. In the embodiment, the signal resistance matching circuit and the signal capacitance matching circuit are added between the circuits, so that the maximum transmission efficiency of long-wave signals is ensured in the transmission process, and the signal processing capability of the filter circuit of the embodiment is improved.
The working principle of the front-end filter circuit of the long-wave receiver of the embodiment is as follows:
the long wave signal input from the signal input terminal enters the three-stage filter circuit formed by the first filter circuit 10, the second filter circuit 20 and the third filter circuit 30, and the long wave signal is filtered in three stages to obtain the filtered signal, and the filtered signal may be too large or too small for the transmitted baseband, in this embodiment, before the filtered signal is transmitted to the baseband, the filtered signal is firstly determined in the gain control circuit 40, when the filtered signal is too large, the filtered signal needs to be correspondingly reduced, as for how many db of gain is reduced, as shown in table 1, when the filtered signal is too small, the filtered signal needs to be correspondingly amplified, as for how many db of gain is amplified, as also shown in table 1, the condition of the adjusted gain of the filtered signal is obtained, the gain adjustment circuit 40 correspondingly adjusts the output filtered signal, and outputs the adjusted filtered signal to the baseband, to complete the function of the front-end filter of the long-wave receiver of the embodiment.
In summary, the multistage operational amplifier of the present embodiment realizes the cascade connection of the active band-pass filters, and has a simple circuit structure and a small volume; on the premise of ensuring that the phase of the long wave signal is not changed, the out-of-band rejection reaches 44dB, and a receiving signal with excellent quality is provided for baseband processing and navigation resolving of a receiver; the circuit of the embodiment has simple design, does not need debugging after the circuit parameter design is finished, has high consistency of circuit performance and is suitable for batch production.
The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.
Claims (7)
1. A long wavelength receiver front end filter circuit, the circuit comprising: a first filter circuit (10), a second filter circuit (20), a third filter circuit (30), a gain control circuit (40), and a gain adjustment circuit (50),
the input end of the first filter circuit (10) is connected with the long wave signal input end, the first filter circuit (10), the second filter circuit (20) and the third filter circuit (30) are sequentially connected, the output end of the third filter circuit (30) is connected with the input end of the gain control circuit (40) and the input end of the gain adjusting circuit (50), the output end of the gain control circuit (40) is connected with the input end of the gain adjusting circuit (50), and the output end of the gain adjusting circuit (50) is connected with the long wave signal output end.
2. The long wave receiver front end filter circuit according to claim 1, characterized in that the first filter circuit (10) comprises operational amplifier A1, operational amplifier A2 and operational amplifier A3, wherein,
the inverting input terminal of the operational amplifier A1 is connected to the long-wave signal input terminal, the output terminal of the operational amplifier A1 is connected to the inverting input terminal of the operational amplifier A2, the output terminal of the operational amplifier A2 is connected to the inverting input terminal of the operational amplifier A3 and the input terminal of the second filter circuit (20), the output terminal of the operational amplifier A3 is connected to the inverting input terminal of the operational amplifier A1, and the non-inverting input terminal of the operational amplifier A1, the non-inverting input terminal of the operational amplifier A2 and the non-inverting input terminal of the operational amplifier A3 are all grounded.
3. The long wave receiver front end filter circuit of claim 2, characterized in that the second filter circuit (20) comprises operational amplifier A4, operational amplifier A5, and operational amplifier A6, wherein,
an inverting input terminal of the operational amplifier a4 is connected to an output terminal of the operational amplifier a2 and an inverting input terminal of the operational amplifier A3, an output terminal of the operational amplifier a4 is connected to an inverting input terminal of the operational amplifier a5, an output terminal of the operational amplifier a5 is connected to an input terminal of the third filter circuit (30) and an inverting input terminal of the operational amplifier A6, an output terminal of the operational amplifier A6 is connected to an inverting input terminal of the operational amplifier a4, and a non-inverting input terminal of the operational amplifier a4, a non-inverting input terminal of the operational amplifier a5, and a non-inverting input terminal of the operational amplifier A6 are all grounded.
4. The long wave receiver front end filter circuit according to claim 3, characterized in that the third filter circuit (30) comprises an operational amplifier A7, an operational amplifier A8 and an operational amplifier A9, wherein,
an inverting input terminal of the operational amplifier a7 is connected to an output terminal of the operational amplifier a5 and an inverting input terminal of the operational amplifier A6, an output terminal of the operational amplifier a7 is connected to an inverting input terminal of the operational amplifier A8, an output terminal of the operational amplifier A8 is connected to the gain control circuit (40), the gain adjustment circuit (50), and an inverting input terminal of the operational amplifier a9, an output terminal of the operational amplifier a9 is connected to an inverting input terminal of the operational amplifier a7, and a non-inverting input terminal of the operational amplifier a7, a non-inverting input terminal of the operational amplifier A8, and a non-inverting input terminal of the operational amplifier a9 are all grounded.
5. The long wave receiver front end filter circuit of claim 4, wherein the operational amplifier A1, the operational amplifier A2 and the operational amplifier A3, the operational amplifier A4, the operational amplifier A5 and the operational amplifier A6, the operational amplifier A7, the operational amplifier A8 and the operational amplifier A9 are all model numbers LT 1365.
6. The long wave receiver front end filter circuit according to claim 1, characterized in that the gain adjustment circuit (50) is a gain amplifier.
7. The long wave receiver front end filter circuit of claim 6, wherein the gain amplifier model is THS7001 IPWP.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920703817.3U CN210016446U (en) | 2019-05-16 | 2019-05-16 | Front-end filter circuit of long-wave receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920703817.3U CN210016446U (en) | 2019-05-16 | 2019-05-16 | Front-end filter circuit of long-wave receiver |
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| Publication Number | Publication Date |
|---|---|
| CN210016446U true CN210016446U (en) | 2020-02-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920703817.3U Expired - Fee Related CN210016446U (en) | 2019-05-16 | 2019-05-16 | Front-end filter circuit of long-wave receiver |
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| Country | Link |
|---|---|
| CN (1) | CN210016446U (en) |
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2019
- 2019-05-16 CN CN201920703817.3U patent/CN210016446U/en not_active Expired - Fee Related
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