Modifica di Electromyography (sezione)

====Filtering====
Even with the aforementioned considerations and the most scrupulous methods, the sEMG signal can still be contaminated by unwanted signals that can be eliminated using various filtering techniques. These techniques are based on circuits (or software programs in the case of digital filters) that allow the useful signals to pass through almost unchanged while strongly attenuating noise or other unwanted signals. For the sEMG signal, filters can pass signals in the band from 20 to 500 Hz, with out-of-band attenuation decreasing by 12 dB/octave, meaning a 12 dB reduction for every doubling or halving of the frequency beyond the minimum and maximum limits.

''Stability of the Electrodes''

Electrode stability refers to mechanical, electrical, and electrochemical stability. Mechanical stability has already been discussed. Electrical and electrochemical stability are related to the progress of the redox reaction that occurs at the electrode's contact with the skin and the skin's electrical characteristics. Problems can usually arise from abnormal changes in the hydration state of the electrode, such as drying out or excessive moisture due to sweat, for example.<ref>J.V. Basmajian and C.J. De Luca, ''Muscles Alive. Their Functions Revealed by Electromyography'', fifth edition (Williams and Wilkins, Baltimore, 1985).</ref>