Signals from 16 differential EMG electrodes can be recorded for 8 hours.

A portable electronic apparatus records electromyographic (EMG) signals in as many as 16 channels at a sampling rate of 1,024 Hz in each channel. The apparatus (see figure) includes 16 differential EMG electrodes (each electrode corresponding to one channel) with cables and attachment hardware, reference electrodes, an input/output-and-power-adapter unit, a 16-bit analog-to-digital converter, and a hand-held computer that contains a removable 256-MB flash memory card. When all 16 EMG electrodes are in use, full-bandwidth data can be recorded in each channel for as long as 8 hours. The apparatus is powered by a battery and is small enough that it can be carried in a waist pouch.

The computer is equipped with a small screen that can be used to display the incoming signals on each channel. Amplitude and time adjustments of this display can be made easily by use of touch buttons on the screen. The user can also set up a data-acquisition schedule to conform to experimental protocols or to manage battery energy and memory efficiently.

This Portable Electromyograph can record signals from as many as 16 differential EMG electrodes. The overall mass of the equipment is 1.1 kg. A wireless version of this device is scheduled for release in the near future.

The software for operation of the apparatus resides in a random-access memory (RAM), with backup power supplied by a small internal lithium cell. A backup copy of this software resides on the flash memory card. In the event of loss of both main and backup battery power and consequent loss of this software, the backup copy can be used to restore the RAM copy after power has been restored.

Accessories for this device are also available. These include goniometers, accelerometers, foot switches, and force gauges.

This work was done by Gianluca De Luca, Carlo J. De Luca, and Per Bergman of DelSys, Inc., for Johnson Space Center. For further information, contact:
DelSys Incorporated
650 Beacon St., 6th floor
Boston, MA 02215
Phone: (617) 236-0599
E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Refer to MSC-23312.