Resolution Below the Least Significant Bit in Digital Systems with Dither

The work was motivated by some common misunderstandings about digital systems. It is commonly believed that small signals or signal details are lost if they are smaller than the quantizing step. Expanding on previous arguments, it is shown that this is not true when the signal to be quantized contains a wide-band noise dither with an amplitude of approximately the step size. The introduction traces the use of dither from video quantization through to its use in audio. quantization error is studied in some detail and the effect of dither is analyzed theoretically and experimentally. By examples of quantized signals it is shown that the dither effectively turns signal distortion into low-level wide-band noise by linearizing the averaged quantizer staircase function, which is as perceived by the ear.