Surface Electromyogram detection

The electromyogram (EMG) is a compound signal comprising the electrical activity of the motor units (MU) activated asynchronously during voluntary muscle contractions. This chapter provides a basic overview of the technologies for the detection and conditioning of surface EMG (sEMG) signals. The first section focuses on electrode technology and the electrode-skin interface. The electrical model of the interface and the effect of electrode characteristics (e.g., size, constituent material) on the features of the detected signal are discussed. The second section describes the most common solutions for the design of the front-end amplifier, signal filtering, and analog-to-digital (A/D) conversion. The third section describes and discusses the use of different configurations of electrodes for the detection of sEMG signals. The concepts of spatial filtering and spatial sampling (mono- and bi-dimensional) are introduced, and the effect of the detection system parameters on the sEMG characteristics is discussed.