| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a delta-sigma modulator which is for outputting a 1-bit pulse density modulation (PDM) signal of a low over-sampling ratio of about 64 times in a high duty ratio of 90% or more and improves stability and fine signal reproducibility. Ž<P>SOLUTION: The delta-sigma modulator relates to a delta-sigma modulator comprising: a high-order loop filter; a first 1-bit quantizer for determining output of the high-order loop filter; a first feedback means for feeding back a first output signal Y1 back to an input stage of the high-order loop filter; a second 1.5-bit type quantizer for determining an output absolute value of an internal stage to be monitored; a second dynamic feedback means for feeding a second output signal Y2 back to the input stage of the high-order loop filter; and a computing element which operates the first output signal Y1 and the second output signal Y2 to produce out a 1-bit PDM signal Y. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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