A noise-shaping quantizer works by feeding extracted quantization error back through a filter.

Evidence

Figure 7.51 shows the block diagram of a noise-shaping quantizer. In it, the quantization error is extracted, fed back via a noise-shaping filter and subtracted from the input. The effect of this can be analyzed as follows, assuming that the output of a quantizer can be considered to be the sum of the input signal and the quantization error. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2667