Dither in Digital Audio Systems
[preliminary version]
Dither is the process of adding noise to a signal before quantization to eleminate all quantization distortion.
Drawback of adding dither to the signal is an increased noise level, but quantization distortion can be eliminated completely, which is a significant advantage especially at low signal levels.
Here are some simulated plots of the transfer function for various types and levels of additive dither. As you can see with the right amount of dither the transfer function can be completely linearized. (click on any image to see a larger version)
No Dither
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1.00 LSB
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1.00 LSB
|
1.00 LSB
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Rectangular Dither
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0.25 LSB
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0.50 LSB
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1.00 LSB
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Triangular Dither
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0.25 LSB
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0.50 LSB
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1.00 LSB
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Triangular Dither, highpass filtered
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0.25 LSB
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0.50 LSB
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1.00 LSB
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Gaussian Dither
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0.50 LSB
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1.00 LSB
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1.50 LSB
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last modified: 2008-04-26
Copyright © by Patrick Piecha