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Ditherómy explanation of how it keeps details below quantization level, Was: "Dither" (TOS #6)
KMD
post Mar 7 2012, 13:22
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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.
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pdq
post Mar 7 2012, 15:07
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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.
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Paulhoff
post Mar 8 2012, 19:03
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QUOTE (pdq @ Mar 7 2012, 10:07) *
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

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


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Posts in this topic
- KMD   Ditherómy explanation of how it keeps details below quantization level   Mar 7 2012, 13:22
- - icstm   QUOTE (KMD @ Mar 7 2012, 12:22) To help w...   Mar 7 2012, 13:29
- - pdq   You might add that even when that small signal DOE...   Mar 7 2012, 15:07
|- - Paulhoff   QUOTE (pdq @ Mar 7 2012, 10:07) You might...   Mar 8 2012, 19:03
- - KMD   icstm - Thanks pdq - true, that is another funct...   Mar 7 2012, 16:10
- - icstm   Spatial dither: In a video feed spatial dither can...   Mar 7 2012, 17:43
- - mjb2006   Please do what you can to improve our wiki article...   Mar 7 2012, 21:43
|- - Notat   QUOTE (mjb2006 @ Mar 7 2012, 14:43) Pleas...   Mar 22 2012, 15:38
- - NullC   I highly recommend the first few sections of this ...   Mar 8 2012, 17:39
|- - icstm   QUOTE (NullC @ Mar 8 2012, 16:39) I highl...   Mar 9 2012, 16:14
- - KMD   Paulhoff - You were probably getting the benefi...   Mar 8 2012, 19:12
- - KMD   NullC - If you put fig 2.4, 2.5 ,2.11, 4.6 in...   Mar 8 2012, 19:15
- - KMD   Reference for this subject. Paper titled, ...   Mar 8 2012, 20:05
- - KMD   mjb2006 - Will do   Mar 9 2012, 15:24
- - greynol   In light of the recent conversation over the quant...   Mar 21 2012, 21:14
|- - mjb2006   QUOTE (greynol @ Mar 21 2012, 14:14) Afte...   Mar 22 2012, 01:57
|- - saratoga   Obviously someone who doesn't understand sampl...   Mar 22 2012, 02:05
- - benski   I remember the first lab in University Physics cla...   Mar 21 2012, 21:42
- - 2Bdecided   Important points: Dither removes the potentially ...   Mar 22 2012, 11:38
- - alanofoz   Warning: very shallow & not very scientific: ...   Mar 22 2012, 12:05


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