Archived posting to the Leica Users Group, 2001/07/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> From: Mxsmanic [mailto:mxsmanic@hotmail.com] > > Austin writes: > > > Can't 20kHz be sampled by a 44.1kHz sampling > > rate? > > Of course, but you seemed to be implying that the extra 4.1 > kHz was required to > resolve 20 kHz, and that is not the case. Even 40.001 kHz > would have sufficed. 40.001 kHz would only suffice if one uses an anti-aliasing filter with an infinitely steep slope. As this is not possible in practice, the extra 4.1 kHz of bandwidth is used to implement the brick-wall filter. Even at that, the early implementations sucked. I have no idea if similar considerations apply in scanning, but I believe I've heard that anti-aliasing filters are placed over CCD arrays in camera to prevent aliasing artifacts. Paul