High Quality Content by WIKIPEDIA articles! In source coding (analog-to-digital conversion and compression), the quantization error is the difference between the actual analog value and quantized digital value due is called quantization error. This error is due either to rounding or truncation. The error is sometimes considered as an additional random signal called quantization noise. Quantization noise is a model of quantization error introduced by quantization in the analog-to-digital conversion (ADC) in telecommunication systems and signal processing. It is a rounding error between the analog input voltage to the ADC and the output digitized value. The noise is non-linear and signal-dependent. It can be modelled in several different ways.