| 202C4 |
|---|
| Sampling rate conversion in the time domain |
| AUTHORS |
| Satoru Miura, Fuminori Kobayashi, Minoru Watanabe (Kyushu Institute of Technology, Iizuka) |
| ABSTRACT |
| Today, sampling rate conversion (SRC) is inevitable, because audio, video and communication are mostly digital and different sampling rates prevail, such as 44.1kHz for CD's and 96kHz for DVD's. Usual SRC is based on the oversampling-filtering-downsampling scheme in the frequency domain, and is widely used. It has, however, a drawback in gate count, especially in the digital filter part when low distortion is necessary. Although time-domain SRC can be efficiently implemented, distortion caused by the interpolation error increases for high frequency signals. Here we present "Fourier interpolation", a novel time-domain SRC scheme. First, DFT is derived for the last four samples; next sine and cosine waves based on the DFT result are generated; the result of added waves is an interpolated time-continuous signal. Some simulations realizing the principle indicated an S/N of 90dB for signals of 1kHz or less in the 44.1kHz to 48kHz conversion. A prototype is implemented on an Altera FPGA with gate count of 400k and its operation verified with Audio Precision System II (AP2). |
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Annual Conference 2002