Oversampling


This applet demostrates the influence of oversampling on the power spectral density and quantization error. For a given quantization word length the noise level can be reduced with the oversampling factor. This applet allows to experiment this noise reduction effect, acoustically by modifying the oversampling and quantization factors, and visually with the spectral representation.

The following functions can be selected on the graphical user interface

  • Quantizer 
    • word length w leads to quantization step size Q=2^(w-1)
  • Dither
    • rect dither - uniform probability density function
    • tri dither - triangular probability density function 
    • high-pass dither - triangular probability density function and high-pass power spectral density
  • Noise shaping 
    • first-order H(z)=z^(-1)
  • Up Sampling Factor  
    • Factors from 4 up to 64 can be tested depending on the cpu performance of your machine.

You can choose between two predefined audio files from our web-server ("audio1.wav" or "audio2.wav") or your own local .wav-file to be processed.

To run the applet you will need at least a Java VM 1.4 or later. Please find the latest JRE (Java Runtime Environment) here.