◄Back

# Long description

A line graph is shown with the X axis labelled tone number. It is marked from 0 to 408 in increments of 17. The Y axis is labelled bits and is marked from 0 (bottom) to 20 (top) in increments of two.

The upstream bits are shown to the left of the graph, in green, starting just after tone number zero, at 0 bits. The graph rises rapidly to a peak of 14 bits at about tone number 17. This is labelled ‘highest bit loading’. It then falls back to zero just before tone number 34.

The downstream bits are shown in red and start where the upstream signal ends. From 0 bits at just before tone number 34, the graph rises rapidly to 12 bits just after tone number 34. At about tone number 51 there is a peak of 13 bits, labelled ‘highest downstream bit loading’. The downstream bits then fluctuate as they drop steadily downwards. At several points, they drop to 0 bits and then rise again to slightly below the original position. The downward fluctuation continues until tone number 365. A few points where the number of bits has fallen to 1 are labelled ‘lowest bit loading’.