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radio:soundcard:sample_rate [2017/01/05 20:53] aldavis created |
radio:soundcard:sample_rate [2017/01/08 09:44] (current) aldavis |
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| Now suppose we use a higher internal data rate, "oversampling". If the card's converter frequency is 192 kHz, half of that is 96 kHz. We need an analog filter to eliminate anything above 96 kHz. For audio, if we care about only up to 20 kHz, this is a very simple filter. If the rate we really want is lower, we need to filter it again, but this is a digital filter. Usually, this would be a "finite impulse response" filter with many sections, so it is very close to ideal. | Now suppose we use a higher internal data rate, "oversampling". If the card's converter frequency is 192 kHz, half of that is 96 kHz. We need an analog filter to eliminate anything above 96 kHz. For audio, if we care about only up to 20 kHz, this is a very simple filter. If the rate we really want is lower, we need to filter it again, but this is a digital filter. Usually, this would be a "finite impulse response" filter with many sections, so it is very close to ideal. | ||
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| + | These filters are used both going in and out. There is also a digital filter as part of any sample rate conversion. In general, the bigger the difference in sample rate, the better the conversion filter works. | ||
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| + | The conclusion here is that it really is worth the extra money for a higher sample rate, even if all of your audio is recorded at the lowest rate. The price difference isn't much. | ||