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Is every line representing a BER measured for a specific bit pattern maybe?
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I believe the multiple lines are just estimates of bit-error rates.
The eye pattern scan tool can be setup to perform bit-error-rates in a couple of ways. The easiest one to understand is the XOR mode - the received signal is split two ways; the normal path and the delayed/offset path. The grid you see in your eye pattern measurement is the bit-error rate at each setting of delay step (x-axis) and offset/voltage (y-axis). The bit error count is the number of times the normal path bit does not match the delayed/offset path, i.e., the number of times the XOR gives an output of 1 (when the inputs are different).
The shape of the eye pattern changes depending on what PRBS/LFSR signal you send it.
Check out these slides for some heat-map images;
https://www.ovro.caltech.edu/~dwh/correlator/pdf/hawkins_jpl_2014.pdf The top of this page has a couple of documents I wrote for the Transceiver Toolkit
https://www.ovro.caltech.edu/~dwh/correlator/cobra_docs.html There may be some additional info in there of use to you. The Arria V GZ transceivers are the same as the Stratix V, so make sure to look at that document too.
Cheers,
Dave
Honored Contributor
