That is an older example and it really should not be set up that way. I’ll fix it.
A better example to look at would be one of the examples in the sub-folder 8 QAM, 16 QAM etc. Here a BER Test Set is used to experimentally count the bit errors. The BER Analyzer is not giving the proper BER because it is hooked up to the signal after it has been detected and regenerated, giving an “ideal” eye diagram, even though some of the bits may have been detected incorrectly.
Regards