| 摘要 |
PROBLEM TO BE SOLVED: To execute highly accurate D/A conversion without depending on the variation frequency, etc., of an input digital signal. SOLUTION: A D/A conversion circuit 2 includes a pulse modulation circuit 4, an adding circuit 114, a D/A converter 116 and a filter 118. The circuit 4 generates 1-bit digital signal 6 varying a logic value by a period corresponding to the value of the low-order m-n bits of the input digital signal 102 of m-bits, and the circuit 114 synchronizes higher-order n-bits except for the low-order bits of the signal 102 and the signal 6 generated by the circuit 4 with a clock signal 122 to digitally add them. The converter 116 converts the output signal of the circuit 114 to an analog signal and the filter 118 removes high frequency components from the output signal of the converter 116 to output it as a final converting result. Then, the circuit 4 consists of a delta/sigma converting circuit and generates the signal 6 closer to an ideal.
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