Engine analyzer with constant width digital waveform display

摘要

An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog electrical input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The digitized input waveform is stored in the form of digital data in a data mamory. Upon request by the operator of the apparatus, a microprocessor selects digital data stored, and supplies that digital data to a display, which displays a visual representation of the waveform based upon the selected digital data. The engine analyzer apparatus produces a constant width waveform regardless of engine RPM, by determining the period of the waveform to be stored, and then varying the sample rate at which the A/D converter samples the analog waveform and converts the sampled waveform to digital data. As a result, the number of data samples, and thus the width of the displayed waveform, is constant.