N-path notch filter with a 43-dB notch depth improvement for power line noise suppression

2016 ◽  
Author(s):  
Nicodimus Retdian ◽  
Takeshi Shima
Keyword(s):  
Noise Suppression ◽  
Notch Filter ◽  
Power Line ◽  
Notch Depth ◽  
Power Line Noise ◽  
Line Noise

scholarly journals Performance Evaluation of Wavelet De-Noising Schemes for Suppression of Power Line Noise in Electrocardiogram Signals

2021 ◽  
Vol 18 (2) ◽  
pp. 144-151
Author(s):  
Y. K. Ahmed ◽  
A.R. Zubair
Keyword(s):  
Noise Suppression ◽  
Power Line ◽  
Biomedical Signal Processing ◽  
Wavelet Domain ◽  
Ecg Signals ◽  
Shrinkage Function ◽  
Electrocardiogram Signals ◽  
Power Line Noise ◽  
Power Line Interference ◽  
Line Noise

Power line noise introduces distortions to recorded electrocardiogram (ECG) signals. These distortions compromise the integrity and negatively affect the interpretation of the ECG signals. Despite the fact that the amplifiers used in biomedical signal processing have high common mode rejection ratio (CMRR), ECG recordings are still often corrupted with residual Power Line Interference (PLI) noise. Further improvement in the hardware solutions do not have significant achievements in PLI noise suppression but rather introduce other adverse effects. Software approach is necessary to refine ECG data. Evaluation of PLI noise suppression in ECG signal in the wavelet domain is presented. The performance of the Hard Threshold Shrinkage Function (HTSF), the Soft Threshold Shrinkage Function (STSF), the Hyperbola Threshold Shrinkage Function (HYTSF), the Garrote Threshold Shrinkage Function (GTSF), and the Modified Garrote Threshold Shrinkage Function (MGTSF) for the suppression of PLI noise are evaluated and compared with the aid of an algorithm. The optimum tuning constant for the Modified Garrote Threshold Shrinkage Function (MGTSF) is found to be 1.18 for PLI noise. GTSF is found to have best performance closely followed by MGTSF in term of filtering Gain. HTSF recorded the lowest Gain. Filtering against PLI noise in the wavelet domain preserves the key features of the signal such as the QRS complex.

scholarly journals A STUDY OF POWER LINE INTERFERENCE CANCELLATION USING IIR, AAPTIVE AND WAVELET FILTERING IN ECG

2014 ◽  
pp. 184-186
Author(s):  
IMTEYAZ AHMAD ◽  
F. ANSARI ◽  
U.K. DEY
Keyword(s):  
Interference Cancellation ◽  
Adaptive Filters ◽  
Signal To Noise Ratio ◽  
Notch Filter ◽  
Power Line ◽  
Ecg Signal ◽  
Notch Filters ◽  
Wavelet Filtering ◽  
Power Line Noise ◽  
Line Noise

Background: It is essential to reduce these disturbances in ECG signal to improve accuracy and reliability. The bandwidth of the noise overlaps that of wanted signals, so that simple filtering cannot sufficiently enhance the signal to noise ratio. The present paper deals with the digital filtering method to reduce 50 Hz power line noise artifacts in the ECG signal. 4th order Butterworth notch filters(BW=.5 Hz) is used to reduce 50 Hz power line noise interference(PLI) from ECG signals and its performance is compared with Adaptve filters. Method: ECG signal is taken from physionet database. ECG signal (with PLI noise of different frequencies) were processed by Butterworth notch filters of bandwidths of 0.5 Hz. Ringing Artifact is observed in the output. ECG signal (with PLI noise of different frequencies) were processed by Adaptive filters no ringing effect seen. Wavelet filtering applied clean ECG were observed. Result: Performance is compared based on SNR and MSE of Butterworth notch filter and adaptive filters and output of wallet filtering were observed. Conclusion: RLS adaptive filter give better performance as compared to IIR Butterworth and LMS. Clean ECG were seen when filtering using symlet8 wavelet was done.

scholarly journals Two-Electrode ECG for Ambulatory Monitoring with Minimal Hardware Complexity

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2386
Author(s):  
Branko Babusiak ◽  
Stefan Borik ◽  
Maros Smondrk
Keyword(s):  
Noise Suppression ◽  
Sampling Rate ◽  
Ambulatory Monitoring ◽  
Power Line ◽  
Hardware Complexity ◽  
Noise Current ◽  
Current Consumption ◽  
Power Line Noise ◽  
Minimal Hardware ◽  
Line Noise

This article introduces a two-electrode ground-free electrocardiogram (ECG) with minimal hardware complexity, which is ideal for wearable battery-powered devices. The main issue of ground-free measurements is the presence of noise. Therefore, noise suppression methods that can be employed for a two-electrode ECG acquisition system are discussed in detail. Experimental measurements of a living subject and patient simulator are used to investigate and compare the performance of the three proposed methods utilizing the ADS1191 analogue front-end for biopotential measurements. The resulting signals recorded for the simulator indicate that all three methods should be suitable for suppressing power-line noise. The Power Spectral Density (PSD) of the signals measured for a subject exhibits differences across methods; the signal power at 50 Hz is −28, −24.8, and −26 dB for the first, second, and third method, respectively. The digital postprocessing of measured signals acquired a high-quality ECG signal comparable to that of three-electrode sensing. The current consumption measurements demonstrate that all proposed two-electrode ECG solutions are appropriate as a battery-powered device (current consumption < 1.5 mA; sampling rate of 500 SPS). The first method, according to the results, is considered the most effective method in the suppression of power-line noise, current consumption, and hardware complexity.

Separation of EOG Artifact and Power Line Noise-50Hz from EEG by Efficient Stone's BSS Algorithm

2014 ◽  
Vol 543-547 ◽  
pp. 2687-2691 ◽  
Author(s):  
Ahmed Kareem Abdullah ◽  
Chao Zhu Zhang ◽  
Si Yao Lian
Keyword(s):  
Notch Filter ◽  
Optimization Procedure ◽  
Power Line ◽  
Eeg Signals ◽  
Separation Algorithm ◽  
Eeg Data ◽  
Temporal Predictability ◽  
Power Line Noise ◽  
Computerized Eeg ◽  
Line Noise

An enhanced blind source separation algorithm based on Stone's BSS approach is proposed, to reject the Electrooculogram (EOG) artifact and power line noise (50Hz) from simulated and real human Electroencephalography (EEG) signals without the notch filter, in order not to lose any useful EEG data around the 50-Hz. The proposed algorithm which called efficient Stones BSS (ESBSS) has been compared with four well-known BSS algorithms over super-Gaussian, sub-Gaussian artifacts and EEG signals with a linear mixture. In Original Stones BSS, the half-life values taken as a constant, typically (hlong≥100 hShort), but in the proposed work, an optimization procedure is used to change these values until the maximum temporal predictability is found. The real EEG data are taken from Imperial College London using a computerized EEG device with eight electrodes placed according to the 10-20 system.

scholarly journals Common-Mode Voltage Reduction in Capacitive Sensing of Biosignal Using Capacitive Grounding and DRL Electrode

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2568
Author(s):  
Tadeas Bednar ◽  
Branko Babusiak ◽  
Michal Labuda ◽  
Milan Smetana ◽  
Stefan Borik
Keyword(s):  
Noise Removal ◽  
Power Line ◽  
Measured Signal ◽  
Common Mode ◽  
Line Frequency ◽  
Electrode Area ◽  
Common Mode Voltage ◽  
Grounding Electrode ◽  
Power Line Noise ◽  
Line Noise

A capacitive measurement of the biosignals is a very comfortable and unobtrusive way suitable for long-term and wearable monitoring of health conditions. This type of sensing is very susceptible to noise from the surroundings. One of the main noise sources is power-line noise, which acts as a common-mode voltage at the input terminals of the acquisition unit. The origin and methods of noise reduction are described on electric models. Two methods of noise removal are modeled and experimentally verified in the paper. The first method uses a passive capacitive grounding electrode, and the second uses an active capacitive Driven Right Leg (DRL) electrode. The effect of grounding electrode size on noise suppression is experimentally investigated. The increasing electrode area reduces power-line noise: the power of power-line frequency within the measured signal is 70.96 dB, 59.13 dB, and 43.44 dB for a grounding electrode area of 1650 cm2, 3300 cm2, and 4950 cm2, respectively. The capacitive DRL electrode shows better efficiency in common-mode noise rejection than the grounding electrode. When using an electrode area of 1650 cm2, the DRL achieved 46.3 dB better attenuation than the grounding electrode at power-line frequency. In contrast to the grounding electrode, the DRL electrode reduces a capacitive measurement system’s financial costs due to the smaller electrode area made of the costly conductive textile.

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