A wave trap

Abstract

The utility model discloses a wave trap device. Voltage following module's signal input end is connected with the signal to be trapped, and voltage following module's signal output end is connected with first stage wave trap module's signal input end, and first stage wave trap module's signal output end is connected with first stage high pass filter module's signal input end, and first stage high pass filter module's signal output end is connected with first stage opposite phase amplification module's signal input end, and first stage opposite phase amplification module's signal output end is connected with second stage wave trap module's signal input end, and second stage wave trap module's signal output end is connected with low pass filter module's signal input end, and low pass filter module's signal output end is connected with second stage high pass filter module's signal input end, and second stage high pass filter module's signal output end is connected with second stage opposite phase amplification module's signal input end. Through cascading two stage wave trap processing, can improve the total suppression ability of interference signal, has significantly enhanced the filter effect to specific frequency band.

Description

Technical Field

[0001] This utility model relates to the field of notch filter technology, and in particular to a notch filter device. Background Technology

[0002] In various power signal detection and processing devices, notch filters are commonly used to filter out interference signals in specific frequency bands (such as power frequency interference) to improve the signal-to-noise ratio. However, existing notch filters have the following drawbacks:

[0003] Current notch filter structures are mostly single-stage designs, with limited notch depth and typical gain suppression capabilities between -30dB and -40dB. For applications with high interference intensity (such as input signals with a signal-to-noise ratio of 1:1000), single-stage notches often fail to meet signal purity requirements, resulting in strong residual noise after filtering, which is detrimental to subsequent processing such as precision sampling, digital filtering, or feature extraction. Utility Model Content

[0004] This invention provides a notch filter device that improves the overall suppression capability of interference signals and significantly enhances the filtering effect on specific frequency bands.

[0005] This utility model provides a notch filter device, comprising: a voltage follower module, a first-stage notch filter module, a first-stage high-pass filter module, a first-stage inverting amplifier module, a second-stage notch filter module, a low-pass filter module, a second-stage high-pass filter module, and a second-stage inverting amplifier module; the signal input terminal of the voltage follower module is connected to the aliased signal to be notched, and the signal output terminal of the voltage follower module is electrically connected to the signal input terminal of the first-stage notch filter module; the signal output terminal of the first-stage notch filter module is electrically connected to the signal input terminal of the first-stage high-pass filter module; the signal output terminal of the first-stage high-pass filter module is electrically connected to the signal input terminal of the first-stage inverting amplifier module, and the signal output terminal of the first-stage inverting amplifier module is electrically connected to the signal input terminal of the second-stage notch filter module; the signal output terminal of the second-stage notch filter module is electrically connected to the signal input terminal of the low-pass filter module; the signal output terminal of the low-pass filter module is electrically connected to the signal input terminal of the second-stage high-pass filter module; and the signal output terminal of the second-stage high-pass filter module is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

[0006] Specifically, it also includes: an optocoupler; the voltage follower module includes: a dual-channel single-pole double-throw switch and a voltage follower operational amplifier; the signal input terminal of the optocoupler is used to connect to a control signal, and the signal output terminal of the optocoupler is electrically connected to the control terminal of the dual-channel single-pole double-throw switch; the signal output terminal of the dual-channel single-pole double-throw switch is electrically connected to the positive input terminal of the voltage follower operational amplifier; the negative input terminal of the voltage follower operational amplifier is electrically connected to the signal output terminal of the voltage follower operational amplifier; the output terminal of the voltage follower operational amplifier is electrically connected to the signal input terminal of the first-stage notch filter module.

[0007] Specifically, the voltage follower module further includes: a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor; the first end of the first voltage divider resistor is connected to the signal output end of the optocoupler, and the second end of the first voltage divider resistor is electrically connected to the normally open contact S1A of the dual-channel single-pole double-throw switch; the first end of the second voltage divider resistor is electrically connected to the second end of the first voltage divider resistor; the second end of the second voltage divider resistor is connected in series with the first end of the third voltage divider resistor; the normally closed contact S1B of the dual-channel single-pole double-throw switch is connected between the second voltage divider resistor and the third voltage divider resistor; and the second end of the third voltage divider resistor is grounded.

[0008] Specifically, the first-stage notch filter module includes: a first-stage first notch operational amplifier, a second-stage first-stage notch operational amplifier, a third-stage first-stage notch operational amplifier, and a fourth-stage first-stage notch operational amplifier; the output terminal of the voltage follower operational amplifier is electrically connected to the positive input terminal of the first-stage first-stage notch operational amplifier, the positive input terminal of the second-stage first-stage notch operational amplifier, the output terminal of the second-stage first-stage notch operational amplifier, the positive input terminal of the third-stage first-stage notch operational amplifier, and the positive input terminal of the fourth-stage first-stage notch operational amplifier; the negative input terminal of the first-stage first-stage notch operational amplifier is electrically connected to the output terminal of the first-stage first-stage notch operational amplifier, the negative input terminal of the second-stage first-stage notch operational amplifier, the output terminal of the second-stage first-stage notch operational amplifier, the negative input terminal of the third-stage first-stage notch operational amplifier, the output terminal of the third-stage first-stage notch operational amplifier, the negative input terminal of the fourth-stage first-stage notch operational amplifier, and the output terminal of the fourth-stage first-stage notch operational amplifier; the output terminal of the fourth-stage first-stage notch operational amplifier is electrically connected to the signal input terminal of the first-stage high-pass filter module.

[0009] Specifically, the first-stage high-pass filter module includes: a first-stage high-pass filter operational amplifier, a first-stage high-pass filter capacitor, and a first-stage high-pass filter resistor; the output terminal of the first-stage fourth notch filter operational amplifier is electrically connected to the positive input terminal of the first-stage high-pass filter operational amplifier through the first-stage high-pass filter capacitor; the positive input terminal of the first-stage high-pass filter operational amplifier is grounded through the first-stage high-pass filter resistor; the negative input terminal of the first-stage high-pass filter operational amplifier is electrically connected to the output terminal of the first-stage high-pass filter operational amplifier; and the output terminal of the first-stage high-pass filter operational amplifier is electrically connected to the signal input terminal of the first-stage inverting amplifier module.

[0010] Specifically, the first-stage inverting amplifier module includes: a first-stage inverting operational amplifier and a first-stage inverting resistor; the output terminal of the first-stage high-pass filter operational amplifier is electrically connected to the negative input terminal of the first-stage inverting operational amplifier through the first-stage inverting resistor; the positive input terminal of the first-stage inverting operational amplifier is grounded; the negative input terminal of the first-stage inverting operational amplifier is electrically connected to the normally closed S2B contact of the dual-channel single-pole double-throw switch; and the output terminal of the first-stage inverting operational amplifier is electrically connected to the signal input terminal of the second-stage notch filter module.

[0011] Specifically, the low-pass filter module includes: a low-pass filter operational amplifier and a low-pass filter voltage divider resistor; the signal output terminal of the second-stage notch filter module is electrically connected to the positive input terminal of the low-pass filter operational amplifier through the low-pass filter voltage divider resistor; the negative input terminal of the low-pass filter operational amplifier is electrically connected to the output terminal of the low-pass filter operational amplifier; and the output terminal of the low-pass filter operational amplifier is electrically connected to the signal input terminal of the second-stage high-pass filter module.

[0012] Specifically, the second-stage high-pass filter module includes: a second-stage high-pass filter operational amplifier and a second-stage high-pass filter capacitor; the output terminal of the low-pass filter operational amplifier is electrically connected to the positive input terminal of the second-stage high-pass filter operational amplifier through the second-stage high-pass filter capacitor; the negative input terminal of the second-stage high-pass filter operational amplifier is electrically connected to the output terminal of the second-stage high-pass filter operational amplifier; and the output terminal of the second-stage high-pass filter operational amplifier is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

[0013] Specifically, the second-stage inverting amplifier module includes: a second-stage inverting operational amplifier, a second-stage inverting amplifier first resistor, and a second-stage inverting amplifier second resistor; the output terminal of the second-stage high-pass filter operational amplifier is electrically connected to the negative input terminal of the second-stage inverting operational amplifier through the second-stage inverting amplifier first resistor; the negative input terminal of the second-stage inverting operational amplifier is electrically connected to the output terminal of the second-stage inverting operational amplifier through the second-stage inverting amplifier second resistor; and the positive input terminal of the second-stage inverting operational amplifier is grounded.

[0014] One or more technical solutions provided in this utility model have at least the following technical effects or advantages:

[0015] 1. Two notch filter modules are cascaded in the signal path. A typical single-stage notch filter module has a gain suppression depth of approximately -35dB, while cascading two stages can increase the overall suppression capability of interference signals to -60dB or even higher, significantly enhancing the filtering effect on specific frequency bands (such as power frequency interference). Theoretically, it can improve input signals with low original signal-to-noise ratios (e.g., 1:1000) to a high-quality signal level close to 1:1, thereby significantly improving the processing efficiency and accuracy of subsequent analog-to-digital converters (ADCs) or digital signal processing modules. This is particularly suitable for applications requiring precise analysis of low-amplitude, weak signals.

[0016] 2. An optocoupler is used to electrically isolate the control signal of the gear shift switch, physically isolating it from the CPU's digital control signal. This structure effectively prevents interference signals caused by electromagnetic interference and voltage surges during gear shifting from directly affecting the CPU main control unit, thereby improving the stability and safety of system operation and preventing adverse consequences such as abnormal control logic, false signal triggering, or even system crashes. This design is particularly suitable for instruments and equipment in high electromagnetic interference or complex electrical environments, improving the overall system reliability.

[0017] 3. Three voltage divider resistors are incorporated into the voltage follower module, forming a multi-range input voltage regulation network. This structure automatically switches to the most suitable range based on the amplitude of the input signal voltage, ensuring the notch filter module always operates within its optimal linear operating range. This avoids overload distortion due to excessively high voltage or insufficient dynamic range due to excessively low voltage. This voltage adaptability design not only guarantees the accuracy of the notch filter module but also provides a more stable and reliable signal foundation for subsequent analog-to-digital conversion and digital signal processing. Attached Figure Description

[0018] Figure 1 A schematic diagram of the overall structure of the notch filter device provided in this embodiment of the present invention;

[0019] Figure 2 A circuit diagram of the voltage follower module in the notch filter provided in this embodiment of the utility model;

[0020] Figure 3 A circuit diagram of the first-stage notch filter module in the notch filter device provided in this embodiment of the utility model;

[0021] Figure 4 Circuit diagrams of the first-stage high-pass filter module and the first-stage inverting amplifier module in the notch filter device provided for embodiments of this utility model;

[0022] Figure 5Circuit diagram of the low-pass filter module, the second-stage high-pass filter module, and the second-stage inverting amplifier module in the notch filter device provided in the embodiment of this utility model;

[0023] Figure 6 The circuit diagram of the power supply module in the notch filter provided in this embodiment of the utility model. Detailed Implementation

[0024] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0025] like Figure 1 As shown in the embodiment of this utility model, the notch filter device includes: a voltage follower module, a first-stage notch filter module, a first-stage high-pass filter module, a first-stage inverting amplifier module, a second-stage notch filter module, a low-pass filter module, a second-stage high-pass filter module, and a second-stage inverting amplifier module. The signal input terminal of the voltage follower module is connected to the aliased signal to be notched, and the signal output terminal of the voltage follower module is electrically connected to the signal input terminal of the first-stage notch filter module. The signal output terminal of the first-stage notch filter module is electrically connected to the signal input terminal of the first-stage high-pass filter module. The signal output terminal of the first-stage high-pass filter module is electrically connected to the signal input terminal of the first-stage inverting amplifier module, and the signal output terminal of the first-stage inverting amplifier module is electrically connected to the signal input terminal of the second-stage notch filter module. The signal output terminal of the second-stage notch filter module is electrically connected to the signal input terminal of the low-pass filter module. The signal output terminal of the low-pass filter module is electrically connected to the signal input terminal of the second-stage high-pass filter module. The signal output terminal of the second-stage high-pass filter module is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

[0026] The structure of the voltage follower module will be described in detail, such as... Figure 2As shown, it also includes: an optocoupler U3; the voltage follower module includes: a dual-channel single-pole double-throw switch U4 and a voltage follower operational amplifier U1A; the signal input terminal of the optocoupler U3 is used to connect to the control signal, and the signal output terminal of the optocoupler U3 is electrically connected to the control terminal of the dual-channel single-pole double-throw switch U4; the signal output terminal of the dual-channel single-pole double-throw switch U4 is electrically connected to the positive input terminal of the voltage follower operational amplifier U1A; the negative input terminal of the voltage follower operational amplifier U1A is electrically connected to the signal output terminal of the voltage follower operational amplifier U1A; the output terminal of the voltage follower operational amplifier U1A is electrically connected to the signal input terminal of the first-stage notch filter module. The power supply terminals of the optocoupler U3, the dual-channel single-pole double-throw switch U4, and the voltage follower operational amplifier U1A are connected to a power supply, and the ground terminals of the optocoupler U3, the dual-channel single-pole double-throw switch U4, and the voltage follower operational amplifier U1A are grounded. Specifically, CPU_A0 and CPU_A1 are I / O control signals issued by the CPU to drive the gear shift switch. To ensure isolation between the CPU's digital signals and the switch control signals, an optocoupler U3 is used for signal isolation. The isolated signal Chan1_A0 is the front-stage voltage divider gear shift control signal; Chan1_A1 is the first-stage amplification factor switching signal. U_in is a mixed voltage signal of power frequency and other frequencies. U4 is a dual-channel single-pole double-throw switch, D1 is the moving blade, S1B is normally closed, and S1A is normally open. Chan1_A0 is a programmable signal that can control the switching of D1, allowing the input voltage signal to switch between different voltage ranges after passing through the voltage divider resistor. U1A is a voltage follower operational amplifier, which plays a role in impedance matching in the circuit, enabling the subsequent amplification circuit to work better.

[0027] The structure of the voltage follower module is further described below. The voltage follower module also includes: a first voltage divider resistor R1, a second voltage divider resistor R2, and a third voltage divider resistor R3; the first end of the first voltage divider resistor R1 is connected to the signal output end of the optocoupler U3, and the second end of the first voltage divider resistor R1 is electrically connected to the normally open contact S1A of the dual-channel single-pole double-throw switch U4; the first end of the second voltage divider resistor R2 is electrically connected to the second end of the first voltage divider resistor R1; the second end of the second voltage divider resistor R2 is connected in series with the first end of the third voltage divider resistor R3; the normally closed contact S1B of the dual-channel single-pole double-throw switch U4 is connected between the second voltage divider resistor R2 and the third voltage divider resistor R3; the second end of the third voltage divider resistor R3 is grounded.

[0028] The structure of the first-stage notch filter module is described in detail, such as... Figure 3As shown, the first-stage notch filter module includes: a first-stage first-stage notch amplifier U5A, a second-stage notch amplifier U5B, a third-stage notch amplifier U5C, and a fourth-stage notch amplifier U5D; the output terminal of voltage follower amplifier U1A is electrically connected to the positive input terminal of the first-stage notch amplifier U5A, the positive input terminal of the second-stage notch amplifier U5B, the output terminal of the second-stage notch amplifier U5B, the positive input terminal of the third-stage notch amplifier U5C, and the positive input terminal of the fourth-stage notch amplifier U5D; the first-stage first... The negative input terminal of notch amplifier U5A is electrically connected to the output terminals of the first-stage first-stage notch amplifier U5A, the second-stage second-stage notch amplifier U5B, the third-stage third-stage notch amplifier U5C, and the fourth-stage fourth-stage notch amplifier U5D. The output terminal of the fourth-stage notch amplifier U5D is electrically connected to the signal input terminal of the first-stage high-pass filter module. The power supply terminals of the first-stage first-stage notch amplifier U5A, the second-stage second-stage notch amplifier U5B, the third-stage third-stage notch amplifier U5C, and the fourth-stage fourth-stage notch amplifier U5D are connected to a power supply, and their ground terminals are grounded.

[0029] Specifically, the first-stage notch filter module consists of an inverting amplifier circuit and two integrating circuits. Pin ① of the first-stage notch filter operational amplifier U5A is a high-pass output with a gain of A. h The first-stage, third-stage notch amplifier U5C has a low-pass output at pin ① with a gain of A. l The first-stage fourth notch amplifier U5D adds the high-pass and low-pass outputs together, and the output signal U2 is the notch signal output.

[0030] (1) Notch frequency To simplify the design, the gain of each stage of this notch filter module is set to 1, i.e. =1, therefore the notch frequency of this circuit is... .

[0031] From the formula Confirmed, in the formula, C=C4=C5, R F =R15=R16, therefore, by selecting appropriate parameters for C4, C5, R15 and R16, the notch frequency of the notch filter network can be made to be 50Hz.

[0032] (2) -3dB bandwidth , The -3dB bandwidth is determined by the gain of the fourth notch amplifier U5D. The passband of this notch network is mainly affected by Parameter influence, Therefore, by selecting appropriate R18, R11, and R17 parameters, the upper and lower stopband cutoff frequencies of the notch filter network can be configured. The gain of the fourth notch amplifier U5D in the first stage notch filter not only affects... The gain value can also affect the notch depth. Therefore, the notch depth can be optimized by adjusting the gain of the fourth notch amplifier U5D in the first stage.

[0033] The structure of the second-stage notch filter module is the same as that of the first-stage notch filter module, and will not be described in detail here.

[0034] The structure of the first-stage high-pass filter module will be described in detail, such as... Figure 4 As shown, the first-stage high-pass filter module includes: a first-stage high-pass filter operational amplifier U1B, a first-stage high-pass filter capacitor C1, and a first-stage high-pass filter resistor R30; the output terminal of the first-stage fourth notch filter operational amplifier U5D is electrically connected to the positive input terminal of the first-stage high-pass filter operational amplifier U1B through the first-stage high-pass filter capacitor C1; the positive input terminal of the first-stage high-pass filter operational amplifier U1B is grounded through the first-stage high-pass filter resistor R30; the negative input terminal of the first-stage high-pass filter operational amplifier U1B is electrically connected to its output terminal; the output terminal of the first-stage high-pass filter operational amplifier U1B is electrically connected to the signal input terminal of the first-stage inverting amplifier module. U2 is the signal output from the first-stage notch filter module. The first-stage high-pass filter operational amplifier U1B forms a high-pass filter circuit, configured with a cutoff frequency of 15Hz through the selection of the first-stage high-pass filter capacitor C1 and the first-stage high-pass filter resistor R30.

[0035] The structure of the first-stage inverting amplifier module is described in detail. The first-stage inverting amplifier module includes: a first-stage inverting operational amplifier U1C and a first-stage inverting resistor R5; the output terminal of the first-stage high-pass filter operational amplifier U1B is electrically connected to the negative input terminal of the first-stage inverting operational amplifier U1C through the first-stage inverting resistor R5; the positive input terminal of the first-stage inverting operational amplifier U1C is grounded; the negative input terminal of the first-stage inverting operational amplifier U1C is electrically connected to the normally closed contact S2B of the dual-channel single-pole double-throw switch U4; the output terminal of the first-stage inverting operational amplifier U1C is electrically connected to the signal input terminal of the second-stage notch filter module. The first-stage inverting operational amplifier U1C forms an inverting amplifier circuit. The U3 signal and the RF signal are input to channel D2 of the dual-channel single-pole double-throw switch U4. Chan1_A1 is a programmable control signal that can control the switching of D2, making the amplification factor A of the first-stage inverting operational amplifier U1C: or .

[0036] The structure of the low-pass filter module will be described in detail, such as... Figure 5As shown, the low-pass filter module includes: a low-pass filter operational amplifier U2A and a low-pass filter voltage divider resistor R41; the signal output terminal of the second-stage notch filter module is electrically connected to the positive input terminal of the low-pass filter operational amplifier U2A through the low-pass filter voltage divider resistor R41; the negative input terminal of the low-pass filter operational amplifier U2A is electrically connected to its output terminal; the power supply terminal of the low-pass filter operational amplifier U2A is connected to a power supply, and the ground terminal of the low-pass filter operational amplifier U2A is grounded; the output terminal of the low-pass filter operational amplifier U2A is electrically connected to the signal input terminal of the second-stage high-pass filter module.

[0037] In this embodiment, the cutoff frequency of the low-pass filter operational amplifier U2A is 95Hz.

[0038] The structure of the second-stage high-pass filter module is described in detail. The second-stage high-pass filter module includes: a second-stage high-pass filter operational amplifier U2B and a second-stage high-pass filter capacitor C2; the output terminal of the low-pass filter operational amplifier U2A is electrically connected to the positive input terminal of the second-stage high-pass filter operational amplifier U2B through the second-stage high-pass filter capacitor C2; the negative input terminal of the second-stage high-pass filter operational amplifier U2B is electrically connected to its output terminal; the power supply terminal of the second-stage high-pass filter operational amplifier U2B is connected to a power supply, and its ground terminal is grounded; the output terminal U2B of the second-stage high-pass filter operational amplifier is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

[0039] In this embodiment, the cutoff frequency of the second-stage high-pass filter operational amplifier U2B is 15Hz.

[0040] The structure of the second-stage inverting amplifier module is described in detail. The second-stage inverting amplifier module includes: a second-stage inverting operational amplifier U2C, a first-stage inverting resistor R6, and a second-stage inverting resistor R43. The output terminal of the second-stage high-pass filter operational amplifier U2B is electrically connected to the negative input terminal of the second-stage inverting operational amplifier U2C through the first-stage inverting resistor R6. The negative input terminal of the second-stage inverting operational amplifier U2C is electrically connected to its output terminal through the second-stage inverting resistor R43. The positive input terminal of the second-stage inverting operational amplifier U2C is grounded. The second-stage inverting operational amplifier U2C is configured to a fixed 10x signal amplification output.

[0041] The structure of the power supply module is described in detail, such as... Figure 6 As shown, the device input power is DC+12V. To provide positive and negative power to the operational amplifier and other chips, a U8 isolated power module is used to output ±VA power and AGND, which is isolated from the input power supply GND. A 47uF electrolytic capacitor is connected in parallel with AGND at the positive and negative power output terminals for power filtering.

[0042] The working principle of the notch filter device provided in this embodiment of the present invention will be explained in detail below:

[0043] The notch filter provided in this embodiment aims to effectively suppress specific frequency components (e.g., 50Hz power frequency) from the input mixed signal, while retaining other effective frequency bands, thereby improving the accuracy and stability of subsequent signal processing. This notch filter consists of a voltage follower module, a first-stage notch filter module, a first-stage high-pass filter module, a first-stage inverting amplifier module, a second-stage notch filter module, a low-pass filter module, a second-stage high-pass filter module, and a second-stage inverting amplifier module connected sequentially. Signals between each module are transmitted and processed sequentially along a predetermined path to complete the notch filtering operation.

[0044] The input signal is first processed by the voltage follower module, which includes an optocoupler, a dual-channel single-pole double-throw switch U4, a voltage follower operational amplifier U1A, and several voltage divider resistors. The input signal channel is dynamically switched through a programmable signal, and the signal is buffered and impedance matched through an operational amplifier, thereby ensuring the input stability and reliability of the subsequent circuit.

[0045] The voltage follower module's output signal is fed into the first-stage notch filter module. This module consists of a notch network formed by multiple operational amplifiers, including inverting amplifiers and integrators, to create band-stop filtering characteristics. Different frequency bands of the signal are extracted through high-pass and low-pass paths, and then band-stop processing is achieved through the output channel composed of adders, thus effectively suppressing signals of specific frequencies (e.g., 50Hz). The notch frequency is determined by the resistors and capacitors in this module; appropriate parameters are selected during the design to precisely set the notch center frequency at the target interference frequency. The -3dB bandwidth and notch depth of this stage module can also be adjusted through the gain configuration of the relevant amplifiers to achieve optimized notch filtering.

[0046] The signal output from the first-stage notch filter module continues to the first-stage high-pass filter module for filtering out low-frequency noise and DC components. This high-pass module uses a resistor-capacitor-operating amplifier structure with a cutoff frequency of 15Hz, effectively suppressing low-frequency interference. The filtered signal is then fed into the first-stage inverting amplifier module, which has programmable amplification factor adjustment capability. This module controls the signal gain based on the inverting operation, providing a suitable level for subsequent notch filtering.

[0047] Furthermore, the signal enters the second-stage notch filter module, whose structure is basically the same as the first-stage notch filter module. It is also based on a multi-stage operational amplifier to build a notch filter network, in order to enhance the overall notch depth and suppression capability, and improve the filtering efficiency of the target frequency.

[0048] The signal after the second-stage notch filter passes sequentially through a low-pass filter module and a second-stage high-pass filter module. The low-pass filter module has a cutoff frequency of 95Hz and is mainly used to suppress high-frequency noise. The second-stage high-pass filter module and the aforementioned high-pass module form a bandpass window, effectively limiting the output signal bandwidth between 15Hz and 95Hz, enhancing signal clarity and bandwidth control accuracy.

[0049] Finally, the processed signal is input to the second-stage inverting amplifier module, which is equipped with a fixed amplification factor (10 times) to compensate for the signal attenuation caused by the previous stage filtering and further shape the signal waveform to ensure that the output signal has good amplitude and phase characteristics.

[0050] Through the above structural design and module linkage, the notch filter provided in this embodiment of the utility model can effectively attenuate signals of a specified frequency, optimize the output signal quality while ensuring the integrity of other frequency components, and is suitable for various signal precision acquisition and filtering application scenarios.

[0051] In summary, the notch filter provided by this utility model improves signal adaptability, enhances anti-interference capability, and increases the overall notch depth and filtering effect to meet the demand for high-quality signal processing in complex application environments.

[0052] Any aspects of this utility model not described in detail are well-known to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and not to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A notch filter device, characterized in that, include: The system comprises a voltage follower module, a first-stage notch filter module, a first-stage high-pass filter module, a first-stage inverting amplifier module, a second-stage notch filter module, a low-pass filter module, a second-stage high-pass filter module, and a second-stage inverting amplifier module. The signal input terminal of the voltage follower module is connected to the aliased signal to be notched. The signal output terminal of the voltage follower module is electrically connected to the signal input terminal of the first-stage notch filter module. The signal output terminal of the first-stage notch filter module is electrically connected to the signal input terminal of the first-stage high-pass filter module. The signal output terminal of the first-stage high-pass filter module is electrically connected to the signal input terminal of the first-stage inverting amplifier module. The signal output terminal of the first-stage inverting amplifier module is electrically connected to the signal input terminal of the second-stage notch filter module. The signal output terminal of the second-stage notch filter module is electrically connected to the signal input terminal of the low-pass filter module. The signal output terminal of the low-pass filter module is electrically connected to the signal input terminal of the second-stage high-pass filter module. The signal output terminal of the second-stage high-pass filter module is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

2. The notch filter device as described in claim 1, characterized in that, Also includes: Optocouplers; The voltage follower module includes: a dual-channel single-pole double-throw switch and a voltage follower operational amplifier; The signal input terminal of the optocoupler is used to connect to the control signal, and the signal output terminal of the optocoupler is electrically connected to the control terminal of the dual-channel single-pole double-throw switch; the signal output terminal of the dual-channel single-pole double-throw switch is electrically connected to the positive input terminal of the voltage follower operational amplifier; the negative input terminal of the voltage follower operational amplifier is electrically connected to the signal output terminal of the voltage follower operational amplifier; and the output terminal of the voltage follower operational amplifier is electrically connected to the signal input terminal of the first-stage notch filter module.

3. The notch filter device as described in claim 2, characterized in that, The voltage follower module further includes: a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor; the first end of the first voltage divider resistor is connected to the signal output end of the optocoupler, and the second end of the first voltage divider resistor is electrically connected to the normally open contact S1A of the dual-channel single-pole double-throw switch; the first end of the second voltage divider resistor is electrically connected to the second end of the first voltage divider resistor; the second end of the second voltage divider resistor is connected in series with the first end of the third voltage divider resistor; the normally closed contact S1B of the dual-channel single-pole double-throw switch is connected between the second voltage divider resistor and the third voltage divider resistor; and the second end of the third voltage divider resistor is grounded.

4. The notch filter device as described in claim 2, characterized in that, The first-stage notch filter module includes: a first-stage first notch operational amplifier, a second-stage first-stage notch operational amplifier, a third-stage first-stage notch operational amplifier, and a fourth-stage first-stage notch operational amplifier; the output terminal of the voltage follower operational amplifier is electrically connected to the positive input terminal of the first-stage first-stage notch operational amplifier, the positive input terminal of the second-stage first-stage notch operational amplifier, the output terminal of the second-stage first-stage notch operational amplifier, the positive input terminal of the third-stage first-stage notch operational amplifier, and the positive input terminal of the fourth-stage first-stage notch operational amplifier; the negative input terminal of the first-stage first-stage notch operational amplifier is electrically connected to the output terminal of the first-stage first-stage notch operational amplifier, the negative input terminal of the second-stage first-stage notch operational amplifier, the output terminal of the second-stage first-stage notch operational amplifier, the negative input terminal of the third-stage first-stage notch operational amplifier, the output terminal of the third-stage first-stage notch operational amplifier, the negative input terminal of the fourth-stage first-stage notch operational amplifier, and the output terminal of the fourth-stage first-stage notch operational amplifier; the output terminal of the fourth-stage first-stage notch operational amplifier is electrically connected to the signal input terminal of the first-stage high-pass filter module.

5. The notch filter device as described in claim 4, characterized in that, The first-stage high-pass filter module includes: a first-stage high-pass filter operational amplifier, a first-stage high-pass filter capacitor, and a first-stage high-pass filter resistor; the output terminal of the first-stage fourth notch filter operational amplifier is electrically connected to the positive input terminal of the first-stage high-pass filter operational amplifier through the first-stage high-pass filter capacitor; the positive input terminal of the first-stage high-pass filter operational amplifier is grounded through the first-stage high-pass filter resistor; the negative input terminal of the first-stage high-pass filter operational amplifier is electrically connected to the output terminal of the first-stage high-pass filter operational amplifier; and the output terminal of the first-stage high-pass filter operational amplifier is electrically connected to the signal input terminal of the first-stage inverting amplifier module.

6. The notch filter device as described in claim 5, characterized in that, The first-stage inverting amplifier module includes: a first-stage inverting operational amplifier and a first-stage inverting resistor; the output terminal of the first-stage high-pass filter operational amplifier is electrically connected to the negative input terminal of the first-stage inverting operational amplifier through the first-stage inverting resistor; the positive input terminal of the first-stage inverting operational amplifier is grounded; the negative input terminal of the first-stage inverting operational amplifier is electrically connected to the normally closed S2B contact of the dual-channel single-pole double-throw switch; and the output terminal of the first-stage inverting operational amplifier is electrically connected to the signal input terminal of the second-stage notch filter module.

7. The notch filter device as described in claim 1, characterized in that, The low-pass filter module includes: a low-pass filter operational amplifier and a low-pass filter voltage divider resistor; the signal output terminal of the second-stage notch filter module is electrically connected to the positive input terminal of the low-pass filter operational amplifier through the low-pass filter voltage divider resistor; the negative input terminal of the low-pass filter operational amplifier is electrically connected to the output terminal of the low-pass filter operational amplifier; the output terminal of the low-pass filter operational amplifier is electrically connected to the signal input terminal of the second-stage high-pass filter module.

8. The notch filter device as described in claim 7, characterized in that, The second-stage high-pass filter module includes: a second-stage high-pass filter operational amplifier and a second-stage high-pass filter capacitor; the output terminal of the low-pass filter operational amplifier is electrically connected to the positive input terminal of the second-stage high-pass filter operational amplifier through the second-stage high-pass filter capacitor; the negative input terminal of the second-stage high-pass filter operational amplifier is electrically connected to the output terminal of the second-stage high-pass filter operational amplifier; the output terminal of the second-stage high-pass filter operational amplifier is electrically connected to the signal input terminal of the second-stage inverting amplifier module.

9. The notch filter device as described in claim 8, characterized in that, The second-stage inverting amplifier module includes: a second-stage inverting operational amplifier, a first second-stage inverting amplifier resistor, and a second second-stage inverting amplifier resistor; the output terminal of the second-stage high-pass filter operational amplifier is electrically connected to the negative input terminal of the second-stage inverting operational amplifier through the first second-stage inverting amplifier resistor; the negative input terminal of the second-stage inverting operational amplifier is electrically connected to the output terminal of the second-stage inverting operational amplifier through the second second-stage inverting amplifier resistor; the positive input terminal of the second-stage inverting operational amplifier is grounded.

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