Capturing Random Events Using Deep Memory Oscilloscopes
Application Notes
When evaluating the purchase of a new digital storage oscilloscope (DSO), the most obvious criteria that evaluators consider include bandwidth, sample rate, memory depth, and number of channels. An often-overlooked characteristic of an oscilloscope is the level of intensity graded display (like an analog scope) and digitizing update rate.
Update rate should be an important consideration for two primary reasons. First, the digitizing update rate of an oscilloscope can greatly affect the usability of the instrument. Second, the oscilloscope’s acquisition/ waveform update rate can affect the statistical probability of capturing infrequent anomalies and glitches. This application note discusses how today’s deep memory oscilloscopes respond to the need for fast acquisition update rates. In particular, it considers two different approaches – using a Fast Acquisition operating mode or the MegaZoom deep memory technology from Keysight Technologies, Inc. These two approaches are examined in terms of their ability to capture infrequent events and, therefore, anomalies and glitches in a design. Whereas vendors of oscilloscopes using a Fast Acquisition mode claim to have faster acquisition rates, this specification probably applies to just a very narrow set of conditions. The real merit of a scope depends on specific applications, some of which will be considered here.