Active Wireless Electrodes for Multichannel Surface Electromyography

An active electrode with a built-in transmitter (a wireless electrode) is developed, which derives surface EMG without skin preparation and conductive paste due to high input impedance. In addition, a reference electrode becomes needless by a built-in stabilized reference circuit. Subjects are less restricted with the present wireless electrode compared with the conventional telemetry system because of no connecting wires between electrodes and the transmitter, and no reference electrode. Moreover, it is not affected by the noise caused by the movement of lead wires. Since the FM transmitter is used in the FM radio band, we can use a commercially available FM radio receiver. The wireless electrode was found to be operated for 29 hours in changes of temperature and with a mechanical shock on the landing moment. Legal license is not required in Japan due to the low transmission power.