This technical paper is part of the DesignCon 2018 proceedings in Track 13 , which covers Applying Test and Measurement Methodology. To learn more about DesignCon, please visit designcon.com.
Abstract:
Various methodologies existed over recent decades for treatment of eye diagrams. These coexist and in some ways collide. One such example is “mask compliance”. From the 1950s through the early 1980s, mask testing consisted of a grease-pencil shape drawn on the reticule of an analog oscilloscope … and instructions to be sure the oscilloscope trace stayed inside or outside of the shape.
With the advent of digital oscilloscopes, methods appeared that approximated this kind of test in a more precise fashion. The grease pencil was abandoned. The mask was more precisely specified and drawn. The matter of detecting and recording a mask violation became more objective.
Fast-forward 20-25 years and we have notions of Bit Error Ratio (BER) and contours of constant BER based on statistical analysis of digitized waveforms and eye diagrams. Mask tests are still around … but few seem to know precisely what they mean; just that they seem prudent. Here, we examine the meaning of Eye diagram mask testing, BER contours, BER and the relationships between them.
Author:
Martin Miller, Teledyne LeCroy