| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-resolution feedback type pulse width modulation A/D converter that can reduce quantization noise folded to a neighborhood of DC by thinning-out processing.SOLUTION: A feedback type pulse width modulation A/D converter containing a feedback type pulse width modulator for converting an analog signal to a pulse width signal has a folding preventing filter which is connected to a rear stage of the feedback type width modulator to remove noise which is folded to a DC side due to thinning-out, a thinning-out circuit for thinning out the output data of the folding preventing filter at a pre-determining thinning-out frequency, and a digital filter which is connected to the thinning-out circuit and remove noise of an unnecessary band from the output data of the thinning-out circuit.SELECTED DRAWING: Figure 1 |
