Quantization error manifests as added noise that reduces the signal-to-noise ratio

Evidence

Although the quantizer will pick the output level that causes minimum error, there will on average always be some error. This error adds noise and distortion to the signal and is often referred to as quantization noise. Ideally this noise should be random and often dither is added to ensure this. The effect of the error is to reduce the signal to noise ratio of the audio signal. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2651

Categorization

• DEFINE: Defines quantization noise and dither as an engineered remedy for it.