Transputer-based parallel system for acquisition and on-line analysis of single-fiber electromyographic signals

We describe a transputer-based system suitable for accurate measurements of single-fiber electromyographic jitter. It consists of a conventional electromyograph, a home-made interface and a commercially available transputer-based board installed within a PC/AT compatible. Taking advantage of the concurrent operation of two transputer modules, the system features simultaneous data acquisition and statistical signal processing: while data are acquired and analyzed, a real-time visualization of the signal latency and its variability is provided. In the present configuration, the system can acquire and analyze up to 40,000 consecutive action potentials, which can be grouped into up to eight sets at different stimulation rates programmable up to 16 Hz. Since the determination of the electromyographic signal latency relies on least-squares smoothing and interpolation of the acquired data rather than on amplitude-threshold triggering, a low value (0.7 microsecond) of so called technical jitter is achieved. Computing power and memory can be easily extended by addition of transputer-based modules. Typical results of data acquisition and on-line analysis are reported.