A crosstalk direction scan holds an unequal lane count of 60 and 40 fixed and compares no crosstalk, forward crosstalk, and reverse crosstalk at the same one-fifth move fraction: no crosstalk leaves 60/40 unchanged, forward crosstalk gives 48/52, and reverse crosstalk gives 68/32 exactly for the stated toy channel rule. Chapter three already compared forward and reverse crosstalk on a symmetric fifty-fifty input, where the two directions are exact mirror images; on this unequal input the two directions genuinely diverge, since moving the same fraction out of the larger lane sends more shots across than moving it out of the smaller lane.
The same unequal lane counts respond differently to no crosstalk, forward crosstalk, and reverse crosstalk. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
An unequal input starts as this chapter's reference
Chapter six's move-fraction scan already used lane counts 60 and 40. With move fraction zero, no crosstalk channel changes those counts at all.
Nnone=(60,40)
The same unequal input responds differently by direction
Chapter three compared forward and reverse crosstalk on a symmetric fifty-fifty input, where the two directions are mirror images of each other. Applied instead to this chapter's unequal sixty-forty input, forward and reverse no longer mirror: the direction interacts with which lane already has more shots to move.
directionnonea-to-bb-to-aNa604868Nb405232
Moving from the smaller lane sends fewer shots across
The reverse direction moves the same one-fifth fraction, but out of the smaller lane. It sends only 8 shots across, less than forward's 12.