A phase encoding row turns each spatial position into a phase value by multiplying position by the gradient scale, so equally spaced positions produce equally spaced phases. With phase scale 2 per meter, positions 0, 1, 2, and 3 m give phases 0, 2, 4, and 6 exactly for the stated toy encoding ledger; real phase encoding needs gradient calibration, timing control, off-resonance and drift handling, and measurement uncertainty.
A phase-encode row is a deterministic position ledger. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A phase scale turns position into phase
The training phase scale is 2 per metre. Each row position is multiplied by that scale.
ϕ/x=2per metre
Four rows make four exact phase values
Positions 0 m, 1 m, 2 m, and 3 m give phases 0, 2, 4, and 6.