Analog-digital hybrid filter for electrocardiosignal noise reduction processing
Through analog digital hybrid filter combined with analog and digital filtering technology, the problem of inflexible noise processing in electrocardiogram signal processing is solved, efficient noise reduction and flexible adaptability are achieved, and signal quality and real-time are improved.
Patent Information
- Application Number
- CN202422745801.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-11-12
AI Technical Summary
The existing electrocardiogram signal filters are not effective when dealing with low-frequency noise, analog filters are difficult to modify filter parameters, digital filters are prone to cause QRS wave group distortion, and the existing technology is not flexible enough to adapt to the characteristics of different patients and scenarios.
An analog digital hybrid filter is used, combined with analog filters and digital filters, and the ECG signal is initially processed through the analog filter, and the digital filter is finely adjusted, including a bandpass filter composed of low-pass and high-pass filters, and a signal amplifier, ADC converter and multi-phase digital filter bank is combined to achieve flexible signal processing.
It improves the signal-to-noise ratio of the ECG signal, reduces power consumption, enhances the flexibility and adaptability of the design, can effectively filter out different types of noise, retain important characteristics of the ECG signal, and adapt to different clinical needs.
Smart Images
Figure CN223260179U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of signal noise reduction, and more particularly to an analog-digital hybrid filter for noise reduction processing of electrocardiogram signals. Background Art
[0002] The electrocardiogram (ECG) is a vital physiological signal for assessing cardiac health, reflecting the heart's electrical activity. As a fundamental physiological signal, its acquisition and analysis are crucial for medical diagnosis. However, due to its relatively weak signal characteristics, with a frequency range generally between 0.05Hz and 100Hz, and an amplitude typically ranging from 100μV (fetal) to 5mV (adult), its signal-to-noise ratio and frequency are relatively low. In practical applications, ECG signals are susceptible to various external interferences, such as baseline drift, myoelectric interference, and power frequency interference, which degrade signal quality and thus affect subsequent analysis and diagnosis. Currently, numerous ECG signal denoising methods exist, which can be broadly categorized into three main types: classic digital filter technology, adaptive filtering, and modern signal processing techniques represented by algorithms such as wavelet transform, mathematical morphology, neural networks, and empirical mode decomposition. Existing analog filters are ineffective at processing low-frequency noise. Once constructed, analog filters constructed from components are difficult to modify, and achieving a minimum stopband attenuation of -60dB is difficult. Classic digital filters and adaptive filtering technologies often suffer from severe QRS complex distortion and loss of inherent high-frequency components when processing ECG signals. Traditional filter designs are often inflexible and struggle to adapt to the ECG signal characteristics of different patients and scenarios. Utility Model Content
[0003] In view of this, the utility model provides an analog-digital hybrid filter for ECG signal noise reduction processing. By combining analog filtering and digital signal processing technology, it can effectively improve the quality of ECG signals, improve the real-time performance of signal processing, reduce power consumption, and enhance design flexibility, thereby better adapting to different clinical needs.
[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0005] An analog-digital hybrid filter for electrocardiogram signal noise reduction processing, comprising an analog filter, a signal amplifier, an ADC converter and a digital filter connected in sequence;
[0006] The analog filter is a bandpass filter, comprising a low-pass filter and a high-pass filter connected in sequence, wherein the low-pass filter comprises a series inductor and a parallel capacitor; the high-pass filter comprises a parallel inductor and a series capacitor, and the RF port connected to the low-pass filter, the series capacitor in the high-pass filter, and the series inductor in the low-pass filter are connected in series to form a RF signal output;
[0007] The output of the radio frequency signal is connected to a signal amplifier, the output port of the amplifier is connected to the analog signal input end of the ADC converter, and the digital signal output port of the ADC converter is divided into multiple paths, which are respectively connected to the digital filter.
[0008] Optionally, the input port of the analog filter includes multiple channels, and multiple digital signal acquisition devices are provided, and outputs of different digital signal acquisition devices correspond to different input channels of the analog filter.
[0009] Optionally, the analog filter front term is provided with a preamplifier module for preamplifying the electrocardiogram signal to obtain a preamplified signal.
[0010] Optionally, the digital filter includes a clock management module, multiple series-parallel conversion modules, a FIFO module, an error correction module, a multi-phase digital filter group, and an output module; the FIFO module is connected to the multi-phase digital filter group through the series-parallel conversion module, and the clock management module and the error correction module are respectively connected to the multi-phase digital filter group; the output of the multi-phase digital filter group is connected to the output module through the series-parallel conversion module.
[0011] Optionally, the error correction module includes a digital signal comparator, and the output signal of the multi-phase digital filter group is input into the digital signal comparator. The digital signal comparator compares the output signal of the multi-phase digital filter group with a preset signal and feeds back the signal to the multi-phase digital filter through a feedback module.
[0012] Optionally, a high-frequency noise filtering circuit is further included, and the high-frequency noise filtering circuit is connected to the electrocardiogram signal acquisition circuit to filter the high-frequency noise signal.
[0013] Optionally, the ECG signal acquisition circuit includes multiple surface electrodes, which are respectively adapted to different parts of the human body; and also includes a feedback circuit and feedback electrodes for providing feedback to the ECG signal acquisition circuit according to human body signs.
[0014] Optionally, the clock management module includes a clock synchronization signal generator, multiple clock gating units and multiple clock division modules; a synchronization signal of a predetermined period is generated by the clock synchronization signal generator; one of the multiple clock gating units is connected in series with one of the multiple clock division modules to form a signal processing branch; the multiple signal processing branches are connected in parallel to receive the source clock signal, the clock gating unit controls the switch of the signal processing branch, and the clock division module is configured to perform phase adjustment on the clock signal of the signal processing branch after receiving the synchronization signal output by the clock synchronization signal generator, so as to adjust the clock signals in the multiple signal processing branches from an asynchronous state to a synchronous state.
[0015] Through the above technical solution, it can be seen that compared with the existing technology, the utility model discloses an analog-digital hybrid filter for ECG signal noise reduction processing. The design of the analog-digital hybrid filter combines the advantages of analog filters and digital filters. It has both the high speed and low power consumption characteristics of analog circuits and the high precision and flexibility of digital circuits. This improvement in comprehensive performance enables the filter to perform well in ECG signal noise reduction processing. At the same time, the filter also has good scalability and adaptability, and can be customized and optimized according to actual needs to meet the needs of different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.
[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0018] Figure 2 This is a schematic diagram of the digital filter of the present utility model. DETAILED DESCRIPTION
[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0020] The present invention discloses an analog-digital hybrid filter for noise reduction of electrocardiogram signals. Figure 1As shown, it includes an analog filter, a signal amplifier, an ADC converter and a digital filter connected in sequence;
[0021] The analog filter is a bandpass filter, comprising a low-pass filter and a high-pass filter connected in sequence, wherein the low-pass filter comprises a series inductor and a parallel capacitor; the high-pass filter comprises a parallel inductor and a series capacitor, and the RF port connected to the low-pass filter, the series capacitor in the high-pass filter, and the series inductor in the low-pass filter are connected in series to form a RF signal output;
[0022] The output of the radio frequency signal is connected to a signal amplifier, the output port of the amplifier is connected to the analog signal input end of the ADC converter, and the digital signal output port of the ADC converter is divided into multiple paths, which are respectively connected to the digital filter.
[0023] The above technical solution has the following beneficial effects:
[0024] As a pre-processing unit, the analog filter effectively removes most noise from ECG signals, especially those with frequencies far from the ECG signal band. The bandpass filter design (combining a low-pass filter and a high-pass filter) ensures that only signals within a specific frequency range pass through, which helps reduce the burden on subsequent digital processing stages.
[0025] Digital filters play a key role in noise reduction. Because digital filters allow for easy adjustment of their parameters and algorithms, filtering strategies can be tailored to the actual noise level of the ECG signal. This helps to more accurately filter out noise while preserving the signal's key characteristics. Furthermore, digital filters can implement a variety of filtering effects, such as adaptive filtering and wavelet transform filtering, to address various types of noise interference. These advanced filtering techniques can further enhance noise reduction in ECG signals.
[0026] Furthermore, the input port of the analog filter includes multiple channels, and multiple digital signal acquisition devices are provided, and the outputs of different digital signal acquisition devices correspond to different input channels of the analog filter.
[0027] Furthermore, the input signal can be split into two signals using a power splitter. Using a single filter structure, one signal is passed through an analog decomposition filter bank, while the other signal passes directly through. Both signals are then sampled by the ADC module, and the output signals are fed into the FPGA for digital filtering. Finally, the output signals are output as four parallel channels.
[0028] The analog-to-digital conversion module in this embodiment uses the AD9434, which can operate in both DDR and SDR modes. In SDR mode, a sample value is acquired on each rising clock edge, with a sampling bit count of 12 bits, and the data is output serially. In DDR mode, a sample value is acquired on each rising and falling clock edge, with a sampling bit count of 6 bits. The data is output in parallel in two channels, with the upper six bits and the lower six bits formatted, while the sampling rate remains unchanged.
[0029] Furthermore, the analog filter front term is provided with a preamplifier module for preamplifying the electrocardiogram signal to obtain a preamplified signal.
[0030] Further, such as Figure 2 As shown, the digital filter includes a clock management module, multiple series-parallel conversion modules, a FIFO module, an error correction module, a multi-phase digital filter group, and an output module; the FIFO module is connected to the multi-phase digital filter group through the series-parallel conversion module, and the clock management module and the error correction module are respectively connected to the multi-phase digital filter group; the output of the multi-phase digital filter group is connected to the output module through the series-parallel conversion module.
[0031] Furthermore, the error correction module includes a digital signal comparator, and the output signal of the multi-phase digital filter group is input into the digital signal comparator. The digital signal comparator compares the output signal of the multi-phase digital filter group with a preset signal and feeds it back to the multi-phase digital filter through a feedback module.
[0032] Furthermore, it also includes a high-frequency noise filtering circuit, which is connected to the electrocardiogram signal acquisition circuit to filter the high-frequency noise signal.
[0033] Furthermore, the ECG signal acquisition circuit includes a plurality of surface electrodes, which are adapted to different parts of the human body respectively; and also includes a feedback circuit and feedback electrodes for providing feedback to the ECG signal acquisition circuit according to the body's physical signs. This embodiment also includes a signal processing device including a display device for displaying the ECG signal in the body and the ECG signal on the surface. Through the display device, medical staff can intuitively see the waveforms of the ECG signal in the body and the ECG signal on the surface, and keep track of the position of the electrodes in the body and the changes in the patient's physiological characteristics at any time. The display device can be a device with a display function, such as a computer, a television, or a mobile phone. More specifically, the first surface electrode is the left lower limb electrode, and the second surface electrode is the right upper limb electrode.
[0034] Furthermore, the clock management module includes a clock synchronization signal generator, multiple clock gating units and multiple clock division modules; a synchronization signal of a predetermined period is generated by the clock synchronization signal generator; one of the multiple clock gating units is connected in series with one of the multiple clock division modules to form a signal processing branch; the multiple signal processing branches are connected in parallel to receive the source clock signal, the clock gating unit controls the switch of the signal processing branch, and the clock division module is configured to adjust the phase of the clock signal of the signal processing branch after receiving the synchronization signal output by the clock synchronization signal generator, and adjust the clock signals in the multiple signal processing branches from an asynchronous state to a synchronous state.
[0035] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.
[0036] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An analog-digital hybrid filter for electrocardiogram signal noise reduction processing, characterized in that: It includes an analog filter, a signal amplifier, an ADC converter and a digital filter connected in sequence; The analog filter is a bandpass filter, comprising a low-pass filter and a high-pass filter connected in sequence, wherein the low-pass filter comprises a series inductor and a parallel capacitor; the high-pass filter comprises a parallel inductor and a series capacitor, and the RF port connected to the low-pass filter, the series capacitor in the high-pass filter, and the series inductor in the low-pass filter are connected in series to form a RF signal output; The output of the radio frequency signal is connected to a signal amplifier, the output port of the amplifier is connected to the analog signal input end of the ADC converter, and the digital signal output port of the ADC converter is divided into multiple paths, which are respectively connected to the digital filter.
2. The analog-digital hybrid filter for ECG signal noise reduction according to claim 1, characterized in that: The input port of the analog filter includes multiple channels, and multiple digital signal acquisition devices are provided. The outputs of different digital signal acquisition devices correspond to different input channels of the analog filter.
3. The analog-digital hybrid filter for ECG signal noise reduction according to claim 1, characterized in that: The analog filter front term is provided with a preamplifier module for preamplifying the electrocardiogram signal to obtain a preamplified signal.
4. The analog-digital hybrid filter for ECG signal noise reduction according to claim 1, characterized in that: The digital filter includes a clock management module, multiple series-parallel conversion modules, a FIFO module, an error correction module, a polyphase digital filter group, and an output module; the FIFO module is connected to the polyphase digital filter group through the series-parallel conversion module, and the clock management module and the error correction module are respectively connected to the polyphase digital filter group; the output of the polyphase digital filter group is connected to the output module through the series-parallel conversion module.
5. The analog-digital hybrid filter for ECG signal noise reduction according to claim 4, characterized in that: The error correction module includes a digital signal comparator, and the output signal of the multi-phase digital filter group is input into the digital signal comparator. The digital signal comparator compares the output signal of the multi-phase digital filter group with a preset signal and feeds back the signal to the multi-phase digital filter through a feedback module.
6. The analog-digital hybrid filter for ECG signal noise reduction according to claim 1, characterized in that: It also includes a high-frequency noise filtering circuit, which is connected to the electrocardiogram signal acquisition circuit to filter the high-frequency noise signal.
7. The analog-digital hybrid filter for ECG signal noise reduction according to claim 6, characterized in that: The ECG signal acquisition circuit includes a plurality of surface electrodes, which are respectively adapted to different parts of the human body; and also includes a feedback circuit and feedback electrodes for providing feedback to the ECG signal acquisition circuit according to human body signs.
8. The analog-digital hybrid filter for ECG signal noise reduction according to claim 4, characterized in that: The clock management module includes a clock synchronization signal generator, multiple clock gating units and multiple clock division modules; a synchronization signal of a predetermined period is generated by the clock synchronization signal generator; one of the multiple clock gating units is connected in series with one of the multiple clock division modules to form a signal processing branch; the multiple signal processing branches are connected in parallel to receive the source clock signal, the clock gating unit controls the switch of the signal processing branch, and the clock division module is configured to adjust the phase of the clock signal of the signal processing branch after receiving the synchronization signal output by the clock synchronization signal generator, so as to adjust the clock signals in the multiple signal processing branches from an asynchronous state to a synchronous state.