The eye pattern represents a high speed BINARY data transfer.
At the center of the eye (where eye height is measured), the data must be stable at HIGH or LOW, so it must be either at a high voltage or a low one, thus the eye height.
At the eye crossing, the data may change (00, 01, 10 or 11), You can see this by the four scope lines (00 = stable low, 01 = scope trace travelling from LOW to HIGH and so on) depending of the data transition.
@jmsa007 The center of the pattern is the point at which the signal clock (somewhere in the background, triggering the oscilloscope which measures the signal) samples the signal. Since this is a digital signal, it must be completely high or low at the sampling point. Otherwise, the ambiguity will lead to data errors. Hence, an "open" eye means that signal is fully high or low at the sample moment. If a signal trace crosses through the eye, then the eye is partially closed, which is bad.
The eye pattern represents a high speed BINARY data transfer.
At the center of the eye (where eye height is measured), the data must be stable at HIGH or LOW, so it must be either at a high voltage or a low one, thus the eye height.
At the eye crossing, the data may change (00, 01, 10 or 11), You can see this by the four scope lines (00 = stable low, 01 = scope trace travelling from LOW to HIGH and so on) depending of the data transition.
ve2zzz 5 months ago
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ve2zzz 5 months ago
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ve2zzz 5 months ago
Still cant understand what does the pattern really represents :(
jmsa007 2 years ago
@jmsa007 The center of the pattern is the point at which the signal clock (somewhere in the background, triggering the oscilloscope which measures the signal) samples the signal. Since this is a digital signal, it must be completely high or low at the sampling point. Otherwise, the ambiguity will lead to data errors. Hence, an "open" eye means that signal is fully high or low at the sample moment. If a signal trace crosses through the eye, then the eye is partially closed, which is bad.
crobc1 11 months ago