| 摘要 |
PROBLEM TO BE SOLVED: To successively output sounds in the condition of preventing the sound quality deterioration even when a power circuit for feeding a digital amplifier with a power source is stopped. SOLUTION: The digital amplifier comprises: a pulse modulator circuit 120 for modulating sound signals; a D class drive circuit 130 driven with the output of the modulator circuit; a filter circuit 140 for smoothing the output of the D class drive circuit; and a DCDC converter 110 for feeding the pulse modulator circuit with power. An attenuator 112 is adjusted according to peculiar signals FLT of the DCDC converter to lower the input gain, thereby avoiding the sound deterioration. COPYRIGHT: (C)2006,JPO&NCIPI
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