EMGworks®

Signal Quality Monitor

Monitor the quality of EMG signals during data acquisition. Automatically. In real-time.

What factors affect EMG Signal Quality?
How to improve EMG signal quality
Signal Quality Monitor

Identify

The best location of the sensor on the muscle for high amplitude EMG signal

Monitor

The quality of the recorded EMG signals throughout the duration of your experiment

Examine

Whether skin preparation is adequate for recording good quality EMG signals

Improve

The quality of your EMG data

EMG signals in real-time

Monitor all EMG signals in real-time. Indicators will warn you if signal quality is not adequate at any time during your recording session.

Explore detailed features of EMG signal quality for each EMG sensor. Rely on meter indicators to obtain quantitative measures.

Signal Quality Features

What indicates good quality EMG signals?

The SNR is the amplitude of the EMG signal recorded during muscle contraction relative to the electrical noise recorded when the muscle is not contracting. The SNR depends on the strength of the contraction and the quality of skin preparation, among other factors. The higher the SNR, the more reliable the discrimination of EMG data from the underlying noise.

High Signal to Noise Ratio (SNR)

The baseline noise represents the amplitude of the electrical signal that is recorded when the muscle is not contracting. It reflects the stability of the skin-electrode interface. The lower the baseline noise, the higher the quality of the EMG signal.

Low Baseline Noise

The line interference is the electrical noise from power lines (50 or 60 Hz) and electrical devices that is present in almost all environments and that may contaminate the recording of EMG signals. Line interference in EMG signals should be kept at a minimum level.

No Line Interference

Clipping occurs when the amplitude of the sEMG signal goes beyond the range that can be reliably recorded by the sensor technology. It may occur if the signal amplification is excessive or if the recording sensor is not properly attached to the skin. No clipping should occur in the EMG signal.

No clipping

How do you Achieve High-Quality sEMG Signals?

The Signal Quality Monitor provides guidance and suggestions to improve the quality of your sEMG signals.

Sensor locationSensor Location

The best location of the sensor is generally on the muscle belly, far from tendon origins and innervation zones. The sensor should be aligned along the direction of the muscle fibers, which typically run longitudinally in a muscle.

Skin PreparationSkin Preparation

For routine applications, the skin surface should be wiped with an alcohol swab to remove oil and debris. For more extreme conditions, such as in case of dry skin, repeatedly apply and peel hypo-allergenic tape to the skin sensor site to remove the outer layer of dead skin.

Sensor AttachmentSensor Attachment

Firmly apply the sensor to the skin to ensure no movement occurs between the sensor contacts and the skin.

Environment

If your EMG signal contains excessive line interference, check your environment for electrical devices that could introduce noise in your recording. Stay as far as possible from external noise sources.