4 ms·
The point of the linked video is to show that this is not the case. If you plot each sample in the PCM audio on your computer screen and draw straight lines bet
by vilhelm_s 12y ago
The point of the linked video is to show that this is not the case. If you plot each sample in the PCM audio on your computer screen and draw straight lines between them it will look like a triangle wave. However, when you play it the sound card will interpolate it back to exactly the same sine wave as you started with. As long as the signal is bandwidth limited to less than the Nyquist limit, sampling and then reconstructing does not introduce distortion.
- auxym 12y agoInteresting, didn't know about the interpolation. Watching the xiph video right now. Out of curiosity, do you have any links that explained how this interp is done?
- vilhelm_s 12y agoI'm not an expert, but I think there are two parts to this. First, "oversampling", meaning that in the digital domain one calculates extra samples in between the given ones to make the "staircase" distortions smaller (see https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/iandm/pdf/chapter11.pdf https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/iandm/pdf/c...). Second, in the analog domain one applies a low-pass "reconstruction filter", similar to the ones used before sampling. The idea is that the noise added by the staircase effect will be high-frequency, and can be filtered out by removing frequencies above the nyquist rate.