Themis;347520 Wrote: > Well, I would have preferred "half wrong" or "half right". Because you > know that D/A converters introduce sinc approximations. No, Pat was correct, and you were wrong. ADC's attempt to measure the instantaneous voltage level at an exact time. They do not measure a "tangential value", and while you might call their errors "approximations" it's more correct to call them what they are: errors.
Themis;347520 Wrote: > Moreover, as you certainly know, any abrupt start and stop of sound > produces distortion (which is the "sic" way of stating that the > sampling theory can't reproduce the sound). Because the theory says > "Any sudden beginning or ending amounts to high frequency content. A > sine burst itself contains a sine wave and a gating wave (turning the > sine on and off). The gate requires infinite bandwidth. A different way > to state this is that the sinc functions at the beginning and end are > truncated.". > This is the reason why we can't produce a perfect saw wave, because it > would require infinite bandwidth. > > So, is there something that I forgot ? You seem to have forgotten Nyquist! Sampling theory clearly states you cannot reproduce infinite bandwidth. If that is your goal, or expectation, then you are correct you'll never achieve it. If you want to digitally reproduce a perfect saw wave, you're out of luck. But, if you're only concerned with human hearing, you can digitally reproduce a saw wave that's been bandwidth limited to 20kHz, perfectly. The same holds true for the sine burst. It won't look the same as a sine burst without the bandwidth limits, on a scope, but you won't be able to hear the differences that you can see (provided the anti-aliasing filter is well designed of course). -- DCtoDaylight Audiophile wish list: Zero Distortion, Infinite Signal to Noise Ratio, and a Bandwidth from DC to Daylight ------------------------------------------------------------------------ DCtoDaylight's Profile: http://forums.slimdevices.com/member.php?userid=7284 View this thread: http://forums.slimdevices.com/showthread.php?t=53355 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
