imageEngineers often refer to a flickering waveform on their oscilloscope’s display as a “waveform ghost”. A waveform ghost is basically an intermittent signal. Sometimes it’s there… sometimes it’s not. Intermittent signals can be spooky.


When your scope is setup to capture a repetitive input signal, perhaps it occasionally captures a wave shape that is different from the normal repetitive stream of waveforms. It could be an infrequent narrow glitch, or an infrequent shift in timing, or an infrequent runt pulse, or anything that is different than what is expected. Reliably capturing random and infrequent waveform anomalies such as these are the most difficult kinds of signal problems to capture, identify, and fix. So what are some of the characteristics of an oscilloscope that can enhance its ability to capture these ghostly waveforms?


This presentation will discuss the various characteristics of oscilloscopes that should be considered when selecting an oscilloscope to debug designs including: bandwidth, sample rate, memory depth, waveform update rate, and triggering. In addition, this presentation will show examples of a new oscilloscope measurement tool called InfiniiScan Zone Triggering that can help you “bust” those troublesome waveform ghosts.




Johnnie Hancock is a Product Manager at Agilent Technologies Oscilloscope Products Division. He began his career with Hewlett-Packard in 1979 as an embedded hardware designer, and holds a patent for digital oscilloscope amplifier calibration. Johnnie is currently responsible for worldwide application support activities that promote Agilent’s digitizing oscilloscopes and he regularly speaks at technical conferences worldwide. Johnnie graduated from the University of South Florida with a degree in electrical engineering. In his spare time, he enjoys spending time with his four grandchildren and restoring his century-old Victorian home located in Colorado Springs.