| 摘要 |
PURPOSE: To reduce an error amount resulting from a process deviation and to make the size of a chip small by allowing an internal D/A converter to charge/discharge charges with a control signal outputted in response to a change in a digital signal so as to minimize the number of passive devices. CONSTITUTION: An interpolation section 1 samples a received digital signal at a prescribed rate. A noise shaping coder 2 quantizes the sampled digital signal to have a prescribed bit number and modulates generated quantization noise. A differentiation device 3 detects a change between adjacent digital signals based on the quantized digital signal. A digital logic section 4 provides an output of a prescribed control signal depending on the detected change between the signals and an internal D/A converter 5 charges or discharges electric charges depending on the control signal. A filter section 6 eliminates noise intruded in the signal component received from the D/A converter 5. Through the configuration above, number of passive devices in use is minimized and errors resulting from a process deviation are reduced and the chip size is made small.
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