Bioelectric signal acquisition system for electroencephalography and evoked potentials

Abstract

Modern equipment for bioelectrical signals recording allow the information storage and analysis in computers, because they convert analog signals in digital signals . In old equipment, the information is recorded in papers, allow its qualitative analysis only . The use of data acquisition boards can solve this problem . This is the main goal of NXl, a data acquisition board developed at the Cuban Neuroscience Center, which is the interface between an external signal conditioner (paper polygraph or evoked potentials equipment) and a computer. This board lets to acquire 16 analog signals with amplitudes ranging from ± 1 V or ± 5 V The maximum sampling frequency possible to achieve is 45 kHz and the recording can be synchronized with external events . It is possible to select the  channel for interrupt request and direct memory access avoiding any conflict with other board . NX1 can be controlled from any program using several procedures and functions developed in Turbo Pascal language . It has been used successfully in biolectrical signals recording and in other applications .