A microprocessor-based system for digitizing seismic events from magnetic-tape recordings

The task of converting analogue recordings of seismic events into digital form for computer input can be rendered faster and more reliable than hand-tracing on a digitizing table by the use of a simple microprocessor-based automatic system. We describe the circuitry and software of a system which takes 4 sec to digitize an event and 40 min to punch a card-deck containing 4096 data points; hand-tracing the same record on a digitizing table takes 8 hr. In addition, the automatic system removes the needs of correcting for duplicate points and axis alignment, and of interpolating to obtain equispaced data points. The system, as described, has been configured at minimal cost for input to an outdated mainframe facility; it demonstrates that microprocessor technology can be used to produce time- and labour-saving gains.