I have figured out how to set the switches so that I get a reasonable picture when I shoot the eye chart on the opposite wall. I can then plot the distribution as a log or linear plot. The above is how a log plot looks. The x axis is ADC count and the y axis is the number of times that count was observed in a million measurements. This is a project being turned on.
Any error is possible.
This is the fun of this business. You can assume that anything can be connected to anything, or that the bit order is reversed in a byte or even random. There are a lot of feedback possibilities. As you know I first suspected that the output bit transitions from the bus were feeding back into the input. DC levels are also sent to the head where switches and the TTL control signals turn them into the desired clocks.