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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 power spectral density of input voltage noise with short circuit inputs
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Figure 4: The power spectral density of input voltage noise with short circuit inputs

Mentions: The designed system was placed in a shield case, and the entire amplifier inputs were connected to the system ground and the outputs were recorded in 10 s minimum in three separate tests. The power spectral density of the recorded signals is depicted in Figure 4. The input voltage noise of the proposed system with the short circuit inputs and a 20 kΩ resistor were shown in Tables 1 and 2, respectively. The former shows the effect of the pure input voltage noise while the latter takes into account the input current noise, as well. The Input voltage noise of different sEMG recording systems in literature was shown for comparison in Table 3.[122021] The Input voltage noise of our system was 0.5595 µV in worst case compared with what obtained by Marateb et al., which was 0.811 µV.[4] Meanwhile, the distribution of the input voltage noise of the four channels was shown in Figure 5. The noise voltage is normally distributed in all channels. In addition, the input noise voltage in all channels was similar [Figures 4 and 5, Tables 1–3].


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 power spectral density of input voltage noise with short circuit inputs
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: The power spectral density of input voltage noise with short circuit inputs
Mentions: The designed system was placed in a shield case, and the entire amplifier inputs were connected to the system ground and the outputs were recorded in 10 s minimum in three separate tests. The power spectral density of the recorded signals is depicted in Figure 4. The input voltage noise of the proposed system with the short circuit inputs and a 20 kΩ resistor were shown in Tables 1 and 2, respectively. The former shows the effect of the pure input voltage noise while the latter takes into account the input current noise, as well. The Input voltage noise of different sEMG recording systems in literature was shown for comparison in Table 3.[122021] The Input voltage noise of our system was 0.5595 µV in worst case compared with what obtained by Marateb et al., which was 0.811 µV.[4] Meanwhile, the distribution of the input voltage noise of the four channels was shown in Figure 5. The noise voltage is normally distributed in all channels. In addition, the input noise voltage in all channels was similar [Figures 4 and 5, Tables 1–3].

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