Patent ID: 6980212

Claim:
A method for automatically detecting unusual waveforms during monitoring of a generally repetitive electrical signal by a digital oscilloscope, the method comprising the steps of: determining a number of “new” pixels affected by each waveform rasterization process after an initial cycle of acquisitions; forming a histogram of a frequency of “new” pixels over a defined cycle of acquisitions, the histogram being updated periodically; using the histogram to define a first threshold number of pixels; comparing the determined number of “new” pixels for a subsequent waveform rasterization with the first threshold number of pixels; if the determined number of “new” pixels is more than the first threshold number of pixels, re-examining the subsequent waveform rasterization to determine a number of “really new” pixels; comparing the determined number of “really new” pixels with a second threshold number of pixels derived from the first threshold number of pixels; and if the determined number of “really new” pixels is more than the second threshold number of pixels, classifying the subsequent rasterized waveform as an unusual waveform.