Another very important parameter in any source encoding scheme is the
level of noise and distortion introduced by the coding process. For waveform encoding, the
main noise source is quantization error, that is, the amplitude errors which the A/D and
D/A conversion process introduces into the signal by not having infinite precision. The
level of quantization noise is dependent on how close any particular sample is to
one of the M levels in the converter. For a speech input, this quantization error
will be manifest as a noise-like disturbance at the output of a D/A converter. |
 |