| 摘要 |
The present invention is an multi stage noise shaping quantizer which includes: a first noise shaping quantizer that includes a first local quantizer which quantizes an input signal and a limiter which limits an output range of the first local quantizer, the first noise shaping quantizer performs noise shaping operation to the input signal; a second noise shaping quantizer that can input a first quantization error which occurs due to quantization operation at the first local quantizer and a limit error which occurs due to a limitation operation to the output range at the limiter as an input and performs noise shaping operation to the input; a differentiator that differentiates an output of the second noise shaping quantizer corresponding to a noise shaping order of the first noise shaping quantizer; an adder that adds an output of the differentiator to an output of the first noise shaping quantizer and output the resultant of the addition; and an amplitude controller that limits an amplitude of the limit error which occurs due to an operation of the limiter according to an output of the first local quantizer and an feedback output of the second noise shaping quantizer.
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