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Designing a Low-noise, High-resolution, and Portable Four Channel Acquisition System for Recording Surface Electromyographic Signal.

Pashaei A, Yazdchi MR, Marateb HR - J Med Signals Sens (2015 Oct-Dec)

Bottom Line: The results indicated that the designed system had several inbuilt operational merits such as low referred to input noise (lower than 0.56 μV between 8 Hz and 1000 Hz), considerable elimination of power-line interference and satisfactory recorded signal quality in terms of signal-to-noise ratio.The estimated values were in then normal ranges.In addition, the system included a modular configuration to increase the number of recording channels up to 96.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran.

ABSTRACT
In current years, the application of biopotential signals has received a lot of attention in literature. One of these signals is an electromyogram (EMG) generated by active muscles. Surface EMG (sEMG) signal is recorded over the skin, as the representative of the muscle activity. Since its amplitude can be as low as 50 μV, it is sensitive to undesirable noise signals such as power-line interferences. This study aims at designing a battery-powered portable four-channel sEMG signal acquisition system. The performance of the proposed system was assessed in terms of the input voltage and current noise, noise distribution, synchronization and input noise level among different channels. The results indicated that the designed system had several inbuilt operational merits such as low referred to input noise (lower than 0.56 μV between 8 Hz and 1000 Hz), considerable elimination of power-line interference and satisfactory recorded signal quality in terms of signal-to-noise ratio. The muscle conduction velocity was also estimated using the proposed system on the brachial biceps muscle during isometric contraction. The estimated values were in then normal ranges. In addition, the system included a modular configuration to increase the number of recording channels up to 96.

No MeSH data available.


Related in: MedlinePlus

The input voltage noise of the acquisition system during rest
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Figure 7: The input voltage noise of the acquisition system during rest

Mentions: sEMG signals were recorded from a biceps brachii muscle of a healthy subject during isometric contractions at 20%, 50%, and 80% of maximum voluntary contraction (MVC) in SD mode. Signals were recorded in 90° flexion angle with at least 10 s duration. Figure 6 shows the signals of four recording channels during isometric contractions at 20% MVC. Figure 7 depicts the input noise of the system for the muscles at rest. The IED in the designed electrode array was 7 mm. The time delay between recording signals of the two channels was calculated using a high-resolution alignment algorithm.[19] To measure the conduction velocity (CV), IED was divided by the calculated time delay. For each contraction, 5 tests were performed and the average CV for the 20%, 50%, and 80% MVC was 5.41054 m/s, 5.21342 m/s, and 5.55196 m/s, respectively which is in the normal range no muscle fatigue was seen at high MVC contractions [Figures 6 and 7].


Designing a Low-noise, High-resolution, and Portable Four Channel Acquisition System for Recording Surface Electromyographic Signal.

Pashaei A, Yazdchi MR, Marateb HR - J Med Signals Sens (2015 Oct-Dec)

The input voltage noise of the acquisition system during rest
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4759841&req=5

Figure 7: The input voltage noise of the acquisition system during rest
Mentions: sEMG signals were recorded from a biceps brachii muscle of a healthy subject during isometric contractions at 20%, 50%, and 80% of maximum voluntary contraction (MVC) in SD mode. Signals were recorded in 90° flexion angle with at least 10 s duration. Figure 6 shows the signals of four recording channels during isometric contractions at 20% MVC. Figure 7 depicts the input noise of the system for the muscles at rest. The IED in the designed electrode array was 7 mm. The time delay between recording signals of the two channels was calculated using a high-resolution alignment algorithm.[19] To measure the conduction velocity (CV), IED was divided by the calculated time delay. For each contraction, 5 tests were performed and the average CV for the 20%, 50%, and 80% MVC was 5.41054 m/s, 5.21342 m/s, and 5.55196 m/s, respectively which is in the normal range no muscle fatigue was seen at high MVC contractions [Figures 6 and 7].

Bottom Line: The results indicated that the designed system had several inbuilt operational merits such as low referred to input noise (lower than 0.56 μV between 8 Hz and 1000 Hz), considerable elimination of power-line interference and satisfactory recorded signal quality in terms of signal-to-noise ratio.The estimated values were in then normal ranges.In addition, the system included a modular configuration to increase the number of recording channels up to 96.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran.

ABSTRACT
In current years, the application of biopotential signals has received a lot of attention in literature. One of these signals is an electromyogram (EMG) generated by active muscles. Surface EMG (sEMG) signal is recorded over the skin, as the representative of the muscle activity. Since its amplitude can be as low as 50 μV, it is sensitive to undesirable noise signals such as power-line interferences. This study aims at designing a battery-powered portable four-channel sEMG signal acquisition system. The performance of the proposed system was assessed in terms of the input voltage and current noise, noise distribution, synchronization and input noise level among different channels. The results indicated that the designed system had several inbuilt operational merits such as low referred to input noise (lower than 0.56 μV between 8 Hz and 1000 Hz), considerable elimination of power-line interference and satisfactory recorded signal quality in terms of signal-to-noise ratio. The muscle conduction velocity was also estimated using the proposed system on the brachial biceps muscle during isometric contraction. The estimated values were in then normal ranges. In addition, the system included a modular configuration to increase the number of recording channels up to 96.

No MeSH data available.


Related in: MedlinePlus