Equation 11 · Part 4 · How AI Datacenter Interconnects Actually Work
subscript
subscript
What this part means
The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.
Its job in the formula
A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.
Full expression→subscript→Article meaning
The passage around this formula
Modern high-rate Ethernet lanes use PAM4 modulation: instead of encoding one bit per symbol as ordinary NRZ signaling does, PAM4 uses four distinct voltage levels to encode two bits per symbol, so a lane’s bit rate runs at twice its baud (symbol) rate rather than matching it one for one. Writing for the symbol rate and for the resulting line rate, . which is exactly the relationship documented for real 400G optics: a 26.5625 Gbaud lane carries 53.125 Gb/s in an eight-lane configuration, and a 53.125 Gbaud lane carries 106.25 Gb/s in a four-lane configuration [ 8 ] . That doubling is not free. Four voltage levels packed into the same…
Learn the underlying idea
A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.
Open the illustrated subscripts: which member of a family? guide →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.