!The Noise Is Exiled To The Edges
Quantization introduces an unavoidable error—the rounding difference between the continuous truth and the discrete step. This error manifests as harsh, uniform white noise spread evenly across all frequencies. Noise shaping does not eliminate this error; it merely rearranges it. By feeding the quantization error back into the input, the system continuously subtracts its own mistakes. This feedback loop acts as a high-pass filter for the noise, aggressively sweeping the static out of the low-frequency baseband where the signal lives, and piling it up in the high-frequency spectrum. The total amount of noise remains the same, but it has been forcefully exiled to the edges of the channel, leaving the center perfectly pure.
