To launch labAlive simulation applications you need a Java Runtime Environment supporting Java Web Start on your system. Here you can get more information about installing the right Java version.
The lesson learned from the uniform quantization experiment is that uniform quantization produces poor quality for small sounds. In this approach, non-uniform quantization should overcome this shortcomming. Logarithmic compressing and expanding (companding) improves the Signal-to-quantization-noise ratio for signals with a large dynamic range like speech. Logarithmic curves like the European A-law are troublesome to implement but can be approximated using piecewise linear segments. In this online simulation app, 13 straight line segments are used - 13-Segment-Kennlinie.
Figure out these questions using the online simulation:
- How much can the Signal-to-quantization-noise ratio improve for low amplitude signals compared to linear / uniform quantization?
- Compare the minimum quantization interval size with uniform quantization!
Listen to signals using the audio play measure (right click on wire):
- Check the sound quality for low signal amplitudes.
External links
Companding: Logarithmic Laws, Implementation, and Consequences
Click on source symbol  |
Select and adjust input signal  |
Click on Quantizer  |
Vary the bit per sample resolution  |
Right click on wire   |
Open any measure for a signal   |
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A sine signal is processed by the compressor to amplify the parts with small amplitudes. |
The same signal after a 6-bit quantization. |
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Finally the expanded signal. You can see a much finer resolution at low signal levels. |
Probability density of the total error. |
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For comparison here is again a uniform quantized signal. |
And here is the same signal processed through a non uniform quantization. |
 Signal-to-quantization-noise ratios of uniform and non-uniform quantization.
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