| 摘要 |
PROBLEM TO BE SOLVED: To effectively reduce higher harmonic wave distortion by utilizing an analog switch and a capacitor for a digital/analog(D/A) converting part without using any bypass capacitor. SOLUTION: A D/A converting part 60 is composed of a reference voltage impressing part 61, digital signal input part 62 for transmitting a digital signal to a 3rd completely symmetric amplifier 63, 3rd completely symmetric amplifier 63 and respective resistor parts 64 for removing higher harmonic wave components. Then, a low-pass filter 70 is provided for reducing the higher- harmonic wave distortion by filtering the output finally outputted from the D/A converting part 60. In this case, concerning the high frequency component generated at a conventional D/A converting part, the high frequency component is removed according to the capacity of a bypass capacitor provided at the D/A converting part but in this case, the high frequency component generated at the 3rd completely symmetric amplifier 63, etc., is removed by the low-pass filter 70 while using the analog switch and the capacitor in place of the bypass capacitor so that the higher harmonic wave distortion can be reduced.
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