資料來源 : Free On-Line Dictionary of Computing
noise shaping
{Spectral noise} transformation in a
quantisation processes. Noise is "colourised" in the {time
domain} an/or {frequency domain} by adding parts of the
previous sample. The {SNR bandwidth} and {SNR time integral}
stay the same, so some noise decreases, some increases, but
overall noise always increases.
An example of noise shaping in the frequency domain is
quantisation of samples on a {Compact Disc} to reduce noise
below -98 dB. The are different algorithms with slightly
different filters, e.g. {Super Bitmapping}, {4D Recording}.
A time domain example is {MPEG-4 AAC TNS}, which is a method
to enhance quality by temporal forming of the noise in a
transform block.
(2003-07-19)