Digital Sound & Music: Concepts, Applications, & Science, Chapter 5, last updated 6/25/2013
53
noise from dither only
noise from dither and noise
shaping
Figure 5.43 Spectral view of noise from dithering and
noise from dithering with noise shaping (quantization noise included)
Noise shaping algorithms, first developed by Cutler in the 1950s, operate by computing
the error from quantizing a sample (including the error from dithering and noise shaping) and
adding this error to the next sample before it is quantized. If the error from the
ith
sample is
positive, then, by subtracting the error from the next sample, noise shaping makes it more likely
that the error for the
i+1st
sample will be negative. This causes the error wave to go up and
down more frequently; i.e., the frequency of the error wave is increased. The algorithm is given
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