Word for the Day Archive

Quantization Error

Error resulting from trying to represent a continuous analog signal with discrete, stepped digital data. The problem arises when the analog value being sampled falls between two digital "steps." When this happens, the analog value must be represented by the nearest digital value, resulting in a very slight error. In other words, the difference between the continuous analog waveform, and the stair-stepped digital representation is quantization error. For a sine wave, quantization error will appear as extra harmonics in the signal. For music or program material, the signal is constantly changing and quantization error appears as wideband noise, cleverly referred to as "quantization noise." It is extremely difficult to measure or spec quantization noise, since it only exists when a signal is present.

Quantization error is one reason higher digital resolutions (longer word lengths) and higher sample rates sound better to our ears; the "steps" become finer, reducing quantization errors.