Dither—my explanation of how it keeps details below quantization level, Was: "Dither" (TOS #6) Options

[KMD]

To help with the understanding of dither, I am posting an explanation, of how signal details smaller than the quantization level are retained, after quantization, when Dither Noise is added to the source material.
A small signal detail with height less than the quantization level, and centred half way between two quantization steps, is too small to cross a quantization step. It is lost when the waveform is quantized. With a Dither Noise waveform added, the height of the two waveforms summed is occasionally greater than the quantization level. At these occasional points the waveform crosses a quantization step. So now when this waveform is quantized, although the result is noisy, the shape of the original signal detail is retained.
Discussion invited.

[pdq]

You might add that even when that small signal DOES cross quantization steps, it will be highly distorted, e.g. converted into a square wave. Dither will then reduce the distortion.

[Paulhoff]

You might add that even when that small signal DOES cross quantization steps, it will be highly distorted, e.g. converted into a square wave. Dither will then reduce the distortion.

This is sooooo true. I had try to record something where the signal was in the lowest digits, and when I added dither to it, it went from being very harsh sounding to noisy and natural sounding


Paul



This post has been edited by Paulhoff: Mar 8 2012, 19:04