| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem wherein distortion happens in a digital amplifying circuit owing to the variations of supply voltage etc. SOLUTION: To a digital amplifying circuit composed of a PWM modulator and an electric power switch, there are added a means for demodulating a PWM output to determine a time-base error and a means for detecting variations of supply voltage. A correction signal to feedback to the PWM output is generated from two error signals. Therefore, distortion due to supply voltage variation or electric power switch non-ideal performance can be reduced. As for the digital voice amplifying device according to the invention, a high-speed and highly accurate A/D converter is made unnecessary, by separating an error detection means for the time direction from the one for the magnitude direction. COPYRIGHT: (C)2005,JPO&NCIPI
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