Abstract: The invention is a method and apparatus for extracting and analyzing features in real time from primary or secondary ignition waveforms, including engine probes, sampling device, and a processor that extracts from the waveform features such as peak firing height, firing line duration, firing line slope, firing line noise, post firing line duration, primary oscillations, and dwell interval duration and compares them against fixed thresholds and running averages to detect anomalies. Anomalies are reported as they occur allowing diagnosis of transient events as well as steady conditions. Waveforms with or without anomalies may be stored and retrieved as needed.

Abstract: An apparatus which permits the automated diagnosis of automobile engine electrical system waveform patterns is disclosed. Employed in conjunction with an addressable random access memory which stores digitized information concerning the waveform are further means which logarithmically reduce input amplitude values of the waveform and coordinates sampling times for the waveform with engine RPM so that the memory capacity is fully utilized. Input conversion of the waveform is accomplished by a tracking analog-to-digital converter using comparator means which also provides a waveform peak detector. Upon an address command, the memory output is input into a read only memory which provides an anti-log conversion of the logarithmic value stored in the memory, thereby providing an output corresponding to an actual value signal.