Instrumentation Back to EMG main page

Volume II (Second Edition) : Atlas of EMG Waveforms
Chapter 1: Instrumentation

1 - Review the basic components of an EMG system.
2 - Study the effects of filter settings on EMG waveforms.
3 - Introduction to digital EMG signal processing.
4 - How to make manual measurements.
5 - Concentric vs Monopolar needle electrodes.
6 - Strategies for reducing noise.
The Instruments:
Analog to Digital

Model M2 Electromyograph

Model JM

Oxford Synergy N2

Block Diagram

Signal Analysis on Digital Electromyograph

Concentric Needle Construction

Concentric Needle Recording

Monopolar Needle Construction

Monopolar Needle Recording

Leads and Cables

Minimising Ambient Noise

Principle of Differential Amplification

How Noise is Attenuated

Common Mode Rejection Ratio

Improving Signal/Noise Ratio

Principle of Filters

Signal and Noise

Low Frequency and Insertional Activity

Low Frequency and Motor Unit Potential

High Frequency and Motor Unit Potential
Analog to Digital

From Analog to Digital

Theory and Theorems

When Sampling Rate is Low

Aliasing in EMG

Spontaneous Activity

Technology or Pathology
Trigger and
Delay Line

Amplitude Trigger

Assessing Motor Unit Potential

Averaging Motor Unit Potential

Noise Reduction with Averaging



Firing Rate <10 Hz

Firing Rate =10 Hz

Firing Rate >10 Hz

Firing Rate =20 Hz
Electrical Safety

Unsafe Operation

Safe Operation

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