| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-stage SRC filter that is more efficient in both computation and a memory request than those of a conventional multi-stage SRC filter. SOLUTION: In this speed conversion method, a sampling speed conversion (SRC) filter is placed in an input sampling data stream with a 1st speed, to generate an output data stream with a 2nd speed different from the 1st speed. The input sampling data stream is processed in a 1st lower-order interpolation routine 42, that produces a 1st intermediate data stream. The 1st intermediate data stream is processed by 1st simplified interpolation filter routines 44, 46, that calculate filter coefficients with a substantially small arithmetic operation scale and generate a 2nd intermediate data stream. The 2nd intermediate data stream is processed in a 1st decimating filter routine 48 that generates an output data stream.
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