| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption while properly setting the sound quality. SOLUTION: A power supply source detection circuit 112 detects battery driving or AC power source driving. An input signal source detection circuit 110 detects a microphone input or a line input. A system control circuit 114 controls an arithmetic operation circuit 105 through a clock control circuit 113 according to the detection results of the circuits 110 and 112. In the case of the battery driving and the microphone input, the arithmetic operation circuit 105 compresses and encodes input audio data by neglecting some lower bits. In the case of the battery driving and the line input, the arithmetic operation circuit 105 compresses and encodes the input audio data by using all the bits thereof. In the case of the AC power source driving, the arithmetic operation circuit 105 compresses and encodes the input audio data by using all the bits thereof. An input signal source detection circuit 111 extracts the detection result information of the detection circuit 110 at the time of recording from reproduced data. The system control circuit 114 controls the arithmetic operation circuit 105 with operation accuracy similar to that at the time of recording. COPYRIGHT: (C)2004,JPO
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