| 摘要 |
PROBLEM TO BE SOLVED: To reduce the noise level of a radio reception band by changing aΔΣmodulation order and aΔΣmodulation sampling frequency, in aΔΣmodulation one-bit signal generating circuit so that higher noise will not coincide with the radio reception frequency band in a one-bit signal amplifier that is mounted on audio equipment. SOLUTION: The one-bit signal amplifier 14 has theΔΣmodulation one-bit signal generating circuit 21, an amplification circuit 22, and a D/A conversion circuit 23. TheΔΣmodulation one-bit signal generating circuit 21 can vary the sampling frequency and the order ofΔΣmodulation and performs theΔΣmodulation of an input signal, that is inputted from one of a plurality of input sources (AM/SW/FM radios, CD, MD) to generate one-bit signals. The amplification circuit 22 amplifies the one-bit signals. The D/A conversion circuit 23 converts the one-bit signals, after the amplification to analog signals. Additionally, the one-bit signal amplifier 14 has sampling frequency switching equipment 24 for setting the sampling frequency, according to the input source of the input signal, andΔΣmodulation order switching equipment 26 for setting theΔΣmodulation order. COPYRIGHT: (C)2004,JPO
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