| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for processing digital signal capable of obtaining a one-bit signal which expresses up to a signal of a large level, while realizing a low quantization noise level by a higher-orderΔΣmodulation for a signal of a small audio band signal level. SOLUTION: The quantization bit number of a quantizer 29 is expanded to 2 bits. Once, aΔΣmodulation signal representing the audio band signal exceeding±1 is generated by using the fifth-orderΔΣmodulator 3 in which the quantization values are 4 values of±1 and±3. The signal converted into 2 bits once is reconverted into one bit signal again by a primaryΔΣmodulator 4 in the subsequent stage. The quantization value of one bit quantizer 33 in the subsequent stage is made the same value as±1 which is the minimum quantization value of the pre-stage 2 bits quantizer 29. COPYRIGHT: (C)2004,JPO
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