| 摘要 |
In the multi-bit A/D converter disclosed by Leslie, since a one-bit feedback is carried out, an output amplitude of an integrator becomes large, and therefore, it is required to be attenuated by a certain constant number time in the analog integrator. Furthermore, a digital quantization noise to be removed is leaked into, and this quantization noise is greatly larger than a quantization noise mixed into with a quantizer, with the result that a SN ratio is remarkably deteriorated. An A/D converter in accordance with the present application includes an n-bit quantizer and a most-significant bit extractor, and further includes a digital processing part receiving an output signal of the most-significant bit extractor, for outputting a sum of the output signal and a value obtained by multiplying a predetermined coefficient and the output signal which was outputted before a predetermined time. Thus, a quantization noise within a signal band can be minimized, and a high precision of conversion can be realized with a low oversampling ratio.
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