Quantization
With the minimum amplitude $A_\mathit{FS-}$ maximum ampitude $A_\mathit{FS+}$ and the number of quantization steps:
$$ \Delta_a = \frac{A_\mathit{FS-} - A_\mathit{FS+}}{N_{\mathit{steps}}} $$
$$ N_{\mathit{steps}} = 2^{N_{\mathit{bits}}} $$
The plot below shows the quantization curve for a 3-bit quantizer - with 8 steps.
Typical bit depths in the history of digital music:
- 8 bit has a very distinc distortion:
- Fairlight CMI
- LinnDrum
- 12 bit is still recognizable:
- E-mu SP-1200
- 16 bit has ben the standard for a long time and only causes artefacts in specific situations:
- CD
- 24 bit makes it almost unnecessary to worry about bit depth:
- today's recording standard in most audio interfaces
- 32 bit ....
- improved recording standard
- representation in DAW's
Quantization Error¶
The quantization error $e$ is calculated as the difference between original and quantized signal:
$$ e = x-x* $$
Spectrum¶
[<matplotlib.lines.Line2D at 0x788dd47b9c40>]