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Plot of gradient waveforms (solid line) and calculated first moment (dashed line) for spins with a velocity of 1 mm/s. The center of the echos (dotted vertical lines) do not occur at the center of the trapezoids due to using a fractional echo to reduce echo times. Note in general the first moment is not nulled on any echo but the accrued angle is small <0.01 radians.
