High-pass filter

Abstract

The utility model relates to the technical field of filters, in particular to a high-pass filter, which comprises a filtering module and a detection module. The filtering module comprises a first-stage filtering circuit and a second-stage filtering circuit, a numerical control potentiometer is arranged in the first-stage filtering circuit, and real-time optimization of feedback compensation is achieved through the numerical control potentiometer and the detection module; a main control chip is arranged in the detection module and can flexibly regulate and control the resistance value of the numerical control potentiometer, gain adjustment of the high-pass filter is achieved, and it is ensured that high-pass filtering can be changed according to needs. The high-pass filter solves the technical problem that an existing high-pass filter cannot adjust feedback parameters in a self-adaptive mode.

Description

Technical Field

[0001] The utility model relates to the technical field of filters, in particular to a high-pass filter. Background Art

[0002] High-pass filters are mainly used to suppress low-frequency signals in signals and retain and enhance high-frequency signals. They are used in many fields such as communication technology, audio processing, image processing, biomedicine, etc., and play a vital role. In the prior art, high-pass filters adjust the stability of the filter by introducing a feedback mechanism to ensure that the filter can work normally and achieve the expected filtering effect. However, the performance of the feedback mechanism is related to the precise feedback parameters. If the parameters are not configured properly, the filter performance may be degraded.

[0003] The patent name that has been made public is a Chinese invention patent with the publication number CN103152000A, which is called "Feedback High-Pass Filter for Airborne Data Acquisition". The high-pass filter in this patent consists of a two-stage series amplifier circuit, which solves the problem of self-oscillation caused by excessive feedback. It has high stability, but the feedback parameters of this patent are fixed, and errors are easily accumulated during continuous operation. It does not have adaptive adjustment capabilities, and its application scenarios are limited, lacking wide applicability. Utility Model Content

[0004] The purpose of the present application is to provide a high-pass filter, which solves the technical problem that the existing high-pass filter cannot adaptively adjust feedback parameters.

[0005] In order to solve the above technical problems, the solution adopted by this application is as follows:

[0006] The utility model provides a high-pass filter, characterized in that: it comprises a filtering module and a detection module; the input end of the detection module is connected to the output end of the filtering module; the filtering module comprises a primary filtering circuit and a secondary filtering circuit;

[0007] The primary filtering circuit comprises a digitally controlled potentiometer and an operational amplifier 1, wherein the negative input terminal of the operational amplifier 1 is connected to the high end of the digitally controlled potentiometer, and the low end of the digitally controlled potentiometer is connected to the middle end of the digitally controlled potentiometer and is grounded; the positive input terminal of the operational amplifier 1 is used as the input terminal of the filtering module;

[0008] The detection module includes an analog-to-digital converter and a main control chip. The clock end and the data signal end of the analog-to-digital converter are respectively connected to the clock end and the data signal end of the main control chip. The data acquisition end of the analog-to-digital converter is connected to an output end of the secondary filter circuit. The three universal ends of the main control chip are respectively connected to the chip selection end, the adjustment end, and the clock end of the digital control potentiometer.

[0009] The input end of the secondary filtering circuit is connected to the output end of the operational amplifier 1, and the second output end of the secondary filtering circuit is set as the output end of the filtering module.

[0010] In some embodiments, the secondary filtering circuit includes an RC filtering circuit, the input end of the RC filtering circuit is connected to the output end of the primary filtering circuit; the RC filtering circuit includes two output ends, and one output end of the RC filtering circuit serves as an output end of the secondary filtering circuit.

[0011] In some embodiments, the secondary filtering circuit further includes operational amplifier 2, the positive input terminal of operational amplifier 2 is connected to the second output terminal of the RC filtering circuit, and the output terminal of operational amplifier 2 serves as the second output terminal of the secondary filtering circuit.

[0012] In some embodiments, the detection module also includes operational amplifier three, the positive input terminal of operational amplifier three serves as the input terminal of the detection module, the output terminal of operational amplifier three is connected to the data acquisition terminal of the analog-to-digital converter, and an output terminal of the secondary filtering circuit is connected to the data acquisition terminal of the analog-to-digital converter through operational amplifier three.

[0013] In some embodiments, the model of the analog-to-digital converter is ADS1115BQDGSRQ1.

[0014] In some embodiments, the analog-to-digital converter is provided with pull-up resistor 1, pull-up resistor 2, and pull-up resistor 3, one end of the pull-up resistor 1, one end of the pull-up resistor 2, and one end of the pull-up resistor 3 are connected and connected to a power supply, and the other end of the pull-up resistor 1, the other end of the pull-up resistor 2, and the other end of the pull-up resistor 3 are respectively connected to the data acquisition end, the clock end, and the data signal end of the analog-to-digital converter.

[0015] In some embodiments, the model of the digitally controlled potentiometer is AD5227BUJZ10-RL7.

[0016] The technical solution of the present application has at least the following advantages and beneficial effects:

[0017] The utility model solves the problem that the existing high-pass filter cannot adaptively adjust feedback parameters. By setting a digitally controlled potentiometer and a detection module, instant optimization of feedback compensation is achieved, and the accuracy of the high-pass filter is significantly improved. The main control chip in the detection module can flexibly adjust the resistance value of the digitally controlled potentiometer, thereby achieving gain adjustment of the high-pass filter, ensuring that the high-pass filter can be changed as needed, broadening the application scenarios of the filter, and enhancing its universal applicability and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a signal flow chart of the utility model.

[0019] Figure 2 This is a schematic diagram of a filter module of the utility model;

[0020] Figure 3 This is a connection diagram of a digital-to-analog converter in the detection module of the utility model. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. If the terms "center", "upper", "lower", "inner", "outer", etc. indicate an orientation or position relationship based on the orientation or position relationship shown in the figure, or the orientation or position relationship in which the product of the application is usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. It should also be noted that unless otherwise clearly specified and limited, if the terms "set", "install", and "connect" appear, they should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] Example 1

[0024] Please refer to Figure 1-Figure 3 The utility model provides a high-pass filter, which is the same as the prior art, and includes a filtering module and a detection module, wherein the input end of the detection module is connected to the output end of the filtering module; the filtering module includes a primary filtering circuit and a secondary filtering circuit.

[0025] The primary filter circuit includes a digitally controlled potentiometer and an operational amplifier 1, wherein the negative input terminal of the operational amplifier 1 is connected to the high end of the digitally controlled potentiometer, and the low end of the digitally controlled potentiometer is connected to the middle end of the digitally controlled potentiometer and is grounded; the positive input terminal of the operational amplifier 1 is used as the input terminal of the filter module;

[0026] The function of the primary filter circuit is to initially suppress low-frequency signals and pass and gain high-frequency signals; the primary filter circuit is provided with a digitally controlled potentiometer, which is used to adjust the feedback parameters of the primary filter circuit, thereby adjusting the gain characteristics.

[0027] The input end of the secondary filter circuit is connected to the output end of the operational amplifier 1, and the second output end of the secondary filter circuit is set as the output end of the filter module;

[0028] The secondary filtering circuit includes an RC filtering circuit, the input end of the RC filtering circuit is connected to the output end of the primary filtering circuit; the RC filtering circuit includes two output ends, one output end of the RC filtering circuit serves as an output end of the secondary filtering circuit; the secondary filtering circuit also includes a second operational amplifier, the positive input end of the second operational amplifier is connected to the second output end of the RC filtering circuit, and the output end of the second operational amplifier serves as the second output end of the secondary filtering circuit;

[0029] The function of the secondary filtering circuit is to further filter the high-frequency signal after gain.

[0030] Further, the filtering module includes capacitors C1, C2, C3, resistors R1, R2, R3, digitally controlled potentiometer U1, operational amplifier one U2, operational amplifier two U3;

[0031] Among them, the first-level filtering circuit includes capacitors C1 and C2, resistors R1 and R2, operational amplifier U2, and digital potentiometer U1; the second-level filtering circuit includes capacitor C3, resistor R3, and operational amplifier U3;

[0032] Specifically, in the filter module, one end of the capacitor C1 is set as the input end of the filter module, and it is called the IN input end, which serves as the input end of the filter module; the other end of the capacitor C1, one end of the resistor R1, and the positive input end of the operational amplifier U2 are connected, and the other end of the resistor R1 is grounded; the pin 7 of the operational amplifier U2 is connected to the power supply, the pin 4 of the operational amplifier U2 is grounded, the negative input end of the operational amplifier U2, one end of the resistor R2, and the high end of the digital potentiometer U1 are connected; the low end and the middle end of the digital potentiometer U1 are connected and grounded, the GND end of the digital potentiometer U1 is grounded, the chip select end of the digital potentiometer U1 is connected to the PA2 pin of the main control chip, the adjustment end of the digital potentiometer U1 is connected to the PA4 pin of the main control chip, and the digital potentiometer The clock end of the digital potentiometer U1 is connected to the PA3 pin of the main control chip, the VDD end of the digital potentiometer U1 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is grounded; the other end of the resistor R2, the output end of the operational amplifier U2, and one end of the capacitor C3 are connected, the other end of the capacitor C3, one end of the resistor R3, and the positive input end of the operational amplifier U3 are connected, and an output end is set here, which is called the out output end, and the out output end is connected to the input end of the detection module; Pin 7 of the operational amplifier U3 is connected to the power supply, Pin 4 of the operational amplifier U3 is grounded, the negative input end of the operational amplifier U3 is connected to the output end of the operational amplifier U3, and the output end here is called the OUT output end, which serves as the second output end of the secondary filtering circuit.

[0033] It needs to be explained that the PA3, PA4, and PA5 pins of the main control chip are all universal terminals; in the secondary filtering circuit, capacitor C3 and resistor R3 form an RC filtering circuit, and the out output terminal is an output terminal of the RC filtering circuit; the role of the operational amplifier U3 here is to protect the previous stage circuit and prevent it from being interfered by the subsequent stage circuit.

[0034] In this embodiment, the model of the digitally controlled potentiometer U1 is AD5227BUJZ10-RL7.

[0035] The detection module includes an analog-to-digital converter and a main control chip. The clock end and the data signal end of the analog-to-digital converter are respectively connected to the clock end and the data signal end of the main control chip. The data acquisition end of the analog-to-digital converter is connected to an output end of the secondary filter circuit. The three universal ends of the main control chip are respectively connected to the chip selection end, the adjustment end, and the clock end of the digital control potentiometer.

[0036] The analog-to-digital converter is provided with a pull-up resistor 1, a pull-up resistor 2, and a pull-up resistor 3. One end of the pull-up resistor 1, one end of the pull-up resistor 2, and one end of the pull-up resistor 3 are connected and connected to a power supply. The other end of the pull-up resistor 1, the other end of the pull-up resistor 2, and the other end of the pull-up resistor 3 are respectively connected to a data acquisition end, a clock end, and a data signal end of the analog-to-digital converter.

[0037] The detection module also includes operational amplifier three, the positive input end of operational amplifier three serves as the input end of the detection module, the output end of operational amplifier three is connected to the data acquisition end of the analog-to-digital converter, and an output end of the secondary filtering circuit is connected to the data acquisition end of the analog-to-digital converter through operational amplifier three.

[0038] Further, the detection module includes a main control chip, an analog-to-digital converter U5, a pull-up resistor one R4, a pull-up resistor two R5, a pull-up resistor three R6, a capacitor C4, and an operational amplifier three U4;

[0039] Specifically, the positive input end of the operational amplifier U4 is set as the in input end, and the in input end is the input end of the detection module; the pin 7 of the operational amplifier U4 is connected to the power supply, the pin 4 of the operational amplifier U4 is grounded, the negative input end of the operational amplifier U4, the output end of the operational amplifier U4, the other end of the pull-up resistor R4, and the data acquisition end of the analog-to-digital converter U5 are connected; the ADDR end of the analog-to-digital converter U5 is connected to the GND end of the analog-to-digital converter U5 and is grounded; one end of the pull-up resistor R4, one end of the pull-up resistor R5, and one end of the pull-up resistor R6 are connected and connected to the power supply, and the other end of the pull-up resistor R5, the clock end of the analog-to-digital converter U5, and the SCL clock end of the main control chip are connected; the other end of the pull-up resistor U6, the data signal end of the analog-to-digital converter U5, and the SDA data signal end of the main control chip are connected; the VDD end of the analog-to-digital converter U5 is connected to one end of the capacitor C4 and connected to the power supply, and the other end of the capacitor C4 is grounded.

[0040] It needs to be explained that the role of operational amplifier U4 here is to protect the front-stage circuit and prevent it from being interfered by the back-stage circuit.

[0041] In this embodiment, the model of the main control chip is STM32F407VET6; the model of the analog-to-digital converter U5 is ADS1115BQDGSRQ1.

[0042] For ease of understanding, the workflow of the present invention is now described:

[0043] The signal is input from the IN input terminal to the primary filter circuit, and the filter circuit filters and gains the signal, initially suppresses the low-frequency signal, amplifies the high-frequency signal, and outputs it to the secondary filter circuit at the same time;

[0044] After receiving the high-frequency signal after gain, the secondary filtering circuit further filters it. After the processing is completed, the final high-frequency signal is output through the out output terminal and the OUT output terminal respectively;

[0045] The high-frequency signal output from the out output terminal is received by the analog-to-digital converter U5 in the detection module. The analog-to-digital converter U5 converts the signal into a digital signal and transmits it to the main control chip. The main control chip makes a judgment based on the expected high-frequency signal.

[0046] If there is a slight deviation between the actual high-frequency signal and the expected high-frequency signal, the main control chip transmits the control signal to the digital potentiometer U1 according to the deviation value. The digital potentiometer U1 adjusts its own resistance, thereby changing the feedback parameters of the first-stage filter circuit to achieve error-free or extremely low-error high-frequency signal output.

[0047] It should be noted that the staff can also adjust the resistance of the digital potentiometer through the main control chip, and then set the feedback parameters of the first-stage filter circuit, so that the feedback parameters of the high-pass filter can be changed as needed, broadening the application scenarios of the filter.

[0048] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution of the present invention, and the scope of the present invention is defined by the attached claims.

Claims

1. A high-pass filter, characterized in that: It includes a filtering module and a detection module; the input end of the detection module is connected to the output end of the filtering module; the filtering module includes a primary filtering circuit and a secondary filtering circuit; The primary filtering circuit comprises a digitally controlled potentiometer and an operational amplifier 1, wherein the negative input terminal of the operational amplifier 1 is connected to the high end of the digitally controlled potentiometer, and the low end of the digitally controlled potentiometer is connected to the middle end of the digitally controlled potentiometer and is grounded; the positive input terminal of the operational amplifier 1 is used as the input terminal of the filtering module; The detection module includes an analog-to-digital converter and a main control chip. The clock end and the data signal end of the analog-to-digital converter are respectively connected to the clock end and the data signal end of the main control chip. The data acquisition end of the analog-to-digital converter is connected to an output end of the secondary filter circuit. The three universal ends of the main control chip are respectively connected to the chip selection end, the adjustment end, and the clock end of the digital control potentiometer. The input end of the secondary filtering circuit is connected to the output end of the operational amplifier 1, and the second output end of the secondary filtering circuit is set as the output end of the filtering module.

2. A high-pass filter according to claim 1, characterized in that: The secondary filtering circuit includes an RC filtering circuit, the input end of the RC filtering circuit is connected to the output end of the primary filtering circuit; the RC filtering circuit includes two output ends, and one output end of the RC filtering circuit serves as an output end of the secondary filtering circuit.

3. A high-pass filter according to claim 2, characterized in that: The secondary filtering circuit also includes an operational amplifier 2, the positive input terminal of the operational amplifier 2 is connected to the second output terminal of the RC filtering circuit, and the output terminal of the operational amplifier 2 serves as the second output terminal of the secondary filtering circuit.

4. A high-pass filter according to claim 1, characterized in that: The detection module also includes operational amplifier three, the positive input end of the operational amplifier three serves as the input end of the detection module, the output end of the operational amplifier three is connected to the data acquisition end of the analog-to-digital converter, and an output end of the secondary filtering circuit is connected to the data acquisition end of the analog-to-digital converter through operational amplifier three.

5. A high pass filter according to claim 1, characterized in that: The model of the analog-to-digital converter is ADS1115BQDGSRQ1.

6. A high-pass filter according to claim 5, characterized in that: The analog-to-digital converter is provided with a pull-up resistor 1, a pull-up resistor 2, and a pull-up resistor 3. One end of the pull-up resistor 1, one end of the pull-up resistor 2, and one end of the pull-up resistor 3 are connected and connected to a power supply. The other ends of the pull-up resistor 1, the other ends of the pull-up resistor 2, and the other ends of the pull-up resistor 3 are respectively connected to a data acquisition end, a clock end, and a data signal end of the analog-to-digital converter.

7. A high pass filter according to claim 1, characterized in that: The model of the digitally controlled potentiometer is AD5227BUJZ10-RL7.

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