EMG System Features

All our EMG systems use pre-amplified EMG electrodes to pick up the electromyographic signal directly from the skin surface or within the subjects muscle using disposable fine-wire electrodes.

The EMG signal from each muscle is individually pre-amplified, band-pass filtered prior to digitization, and then converted to a binary sample for each of the channels. These operations are all performed directly in the subject back-pack to maximize signal quality. The binary information is then sent from the subject back-pack unit, via a single lightweight cable, to the desktop unit where it checked for transmission accuracy and then converted to an analog signal suitable for almost any analog data recording system. The desktop unit provides full electrical safety isolation for the subject.

All MA-300 EMG systems, (6, 10 and 16 EMG channel systems) include the following features:

  • An individual, 10 position, gain switch on each EMG channel allowing optimal signal levels to be recorded over a wide range of signal levels from any muscle, whether spastic, atrophied or healthy.
  • Individual signal level LED on every EMG channel, allowing the user to instantly detect and correct EMG signal problems.
  • Variable low pass filters across all EMG channels to eliminate the possibility of aliasing interference in the recorded EMG signal.
  • Internal calibration signal generation, allowing the user to record a calibration level across all EMG channels to verify correct operation and allowing the system to measure EMG levels in terms of microvolts at skin surface.
  • Eight additional switch inputs are included - suitable for gait event or measurement event recording - each system includes event switches and cables in addition to the EMG channels.
  • Four low speed channels (DC to 120Hz) are included, allowing the addition of goniometers, heart rate monitors etc to the basic system configuration without reducing the EMG channel count.
  • Reliable and easy to us - our system do not require any user configuration or setup. Simply plug in the system and start recording research quality EMG signals.
  • Quality construction - our systems are built tough for regular use. We use metal housings throughout to handle the punishment that all systems receive during normal day to day use in clinical, educational and research facilities. We use quality components throughout the manufacturing process, ensuring that our systems last for years under almost any conditions.
  • Compatible with all major gait and motion analysis systems as well as allowing standalone operation with separate analog data collection system.
  • Real time EMG display available allowing the user to see exactly what is being recorded as the muscle contracts. There is no substitute for real time EMG signal monitoring whether you are recording clinical, investigational, or research electromyography signals.
  • All MA-300 systems are certified by Underwriters Laboratories with CE, UL, CSA, IEC601and FCC Class B certification.
  • Safety is guaranteed - all MA-300 systems are tested to ensure that they provide a minimum of 2.5kV AC fail-safe electrical isolation for the subject.
  • A two year warranty on all major components (excluding preamplifiers, event switches and cables).
Preamplifiers

Each system includes a surface preamplifier for each EMG channel. An interchangeable discrete preamplifier is available as an option for use with disposable gel electrodes and needle electrodes for fine-wire recordings. Both preamplifiers have identical electrical specifications and feature a high input impedance, differential front end design with an overall gain of x20. Our standard preamplifiers have a frequency bandwidth of 20-3000Hz resulting in an overall system bandwidth of 20-2000Hz -3dB when used with the backpack. The preamplifier low frequency response can be modified, on request, to meet the ISEK 10Hz low frequency response requirement to produce a system bandwidth of 10-2000Hz, -3dB for research requirements.

Subject Backpack

Digitizes the full bandwidth data on the subject for maximum accuracy from DC to 2,000Hz -3dB. The backpack contains the digital data transmission module plus electrode and event switch processing circuitry. It provides individual EMG gain controls and EMG signal level indicators as well as an adjustable digital anti-alias filter for all EMG channels. The backpack is easily attached to jackets and belts (supplied) worn by the subject. Powered by the desktop unit, it transfers the digitized EMG data back to the Desktop unit via a rugged, yet ultra-thin, cable that can be up to 120 feet long.

Desktop Unit

Decodes EMG and event switch data to produce standard analog signals (± 5 volt levels) suitable for any analog recording system or Motion Capture ADC interface. The desktop unit provides complete digital signal processing for low noise and zero interference. It provide electrical isolation for the subject and supplies isolated DC power to the subject backpack. It has an auto-sensing 120 - 240 Volt UL approved, medical grade, AC power supply with works anywhere in the world without needing any adjustment.

Options Available

An inexpensive upgrade is available to support either 10 or 16 EMG channels. Integrated Band Pass Filter (25-120 Hz. High Pass and 300-2200 Hz. Low Pass). Subject jackets and belts in various sizes for both adults and children. User-friendly EMG Graphing and EMG Analysis software packages. Additional EMG pre-amplifiers and event switches are available. Other options under development - please ask.

Low Pass (anti-alias) filter

Every MA-300 system provides a full DC to 2000 Hz frequency response for all EMG channels at the backpack. In addition, unlike other EMG systems, each MA-300 includes adjustable low pass filters across all EMG channels as part of the basic design allowing the user to match the frequency response of the EMG data to their data collection system. This avoids the signal aliasing problems of so many other EMG systems that can only be cured by purchasing additional filtering capabilities.

We consider signal aliasing errors to be one of the most common problems with EMG recording because it can only be eliminated prior to the data recording process and, once it has occurred, it is impossible to remove and very difficult to detect. The ten position MA-300 anti-alias filter can be used to eliminate the possibility of signal aliasing errors thus improving your confidence in the recorded EMG data.

Confidence

The MA-300 system uses an ultra-light coaxial cable to transfer data from the subject, and simultaneously supply isolated DC power to the backpack. Unlike radio telemetry systems, you always have the confidence that your EMG signal is reliable and accurate, the system requires no setting up, and there are no batteries to worry about so data collection sessions can run for long periods of time. We believe that the best EMG system for a gait or motion analysis lab is one that you can set up and use without worrying about data quality or battery life - it should be ready to go at any time.

In addition, each MA-300 incorporates sophisticated error-detection and error-correction circuitry that checks the validity of each data sample and corrects and reports any data corruption while the signal data is transferred from the back-pack to the desk-top unit. This feature works so well that, in the unlikely event that the coaxial cable becomes damaged during a session, we have seen users twist the broken cable ends together and finish the data collection session without any problems!

All MA-300 systems have received US FDA 510(k) clearance for use as a diagnostic electromyograph for medical purposes in a clinical environment.

Every MA-300 system is covered by a full two year warranty on both the backpack and desktop units, electrodes, cables, and jackets are covered by a thirty day warranty. We stock all accessories for our equipment and replacement items are always readily available.