Analog reconfigurable technologies for EMG signal processing

*Autor para correspondência Abstract The acquisition and processing of electromyographic (EMG) signals are important steps for clinical applications involving the diagnosis of diseases, and also for the control of myoelectric prostheses or functional electrical stimulation systems. EMG signals are usually processed using analog circuits such as instrumentation amplifiers, filters, RMS converters or rectified average value converters. The design of such traditional circuits, however, especially during the validation phase, is time-consuming. This paper describes the development of an innovative biomedical application using commercially available Field Programmable Analog Arrays (FPAAs). All the functions required for the utilization of EMG signals were implemented using the resources of a single FPAA. The circuit can be configured at any time, either through a new download or through on-the-fly updates to an already functioning configuration. FPAA circuit model AN221E04 enabled the acquisition of low amplitude biopotentials (10 μV to 500 μV) with high common mode interference. The programmable circuit proved to be flexible, since it was possible to modify analog circuit characteristics such as filter cut-off frequencies, gains and reference voltages by software and during circuit operation. The high consumption of the circuit is the main limiting factor, once batteries supply are needed for galvanic isolation.