WIRELESS EEG/EMG DATA ACQUISITION DEVICE FOR USE AS A CONTROL INPUT AND FOR RESEARCH STUDIES
by International Functional Electrical Stimulation Society
Electromyography (EMG) records the electrical activity produced by skeletal muscles. It records various types of muscle signals from simple relaxation by using placing electrodes on the subject’s forehead, to complex neuromuscular feedback during stroke rehabilitation. The EMG signals are acquired from the electrodes applied over or nearby the muscles to be monitored. The electrodes delegates signals to the amplifier unit, usually consisting of high performance differential amplifiers. The usual types of the signal of the interest are in the range of 0.1–2000 mV amplitude, over a bandwidth of about 25–500 Hz.
Although many electrodes still connect to an amplifier using wires, some amplifiers are small enough to mount directly on the electrode. Some minimal specifications for a modern EMG amplifier includes:
- Low internal noise (<0.5 mV)
- High input impedance (>100 MΩ)
- Flat bandwidth and sharp high and low frequency cutoffs (>18 dB/octave).
- High common mode rejection ratio (CMRR > 107 dB)
- Common mode input range (CMR > ±200 mV)
- Static electricity shock protection (>2000 V)
- Gain stability > ±1%