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On Mon, 09 Feb 1998 17:06:15 -0700 (MST), billy@MIX.COM wrote: >> >22kHz is a bit high for a 44.1kHz sampling rate - the high frequency >> >limit is one half the sampling rate... >> > >> I don't quite understand (for a change. <g> ). Could you explain that >> again, please? > >In the world of digital sound recording and transmission there is >what's called (I believe) Shannon's law (many years since I was in >school) which says the highest frequency that can be digitized is >one-half the digital sampling rate. Thus a 44.1kHz sample rate >system can only go up to 22.05kHz. Then there are anti-aliasing >low-pass filters to enforce this, but they are not perfect so there's >some gradual decline in frequency response before hitting the actual >cutoff point. Since in this case you are only 50Hz away in practice >there will not be much left of your signal after going through this >filter. > >For what it's worth any decent analog tape recorder running at >15 ips (inches per second) or faster would record this quite well. >Or if you could sample at 48kHz you might have a chance of getting >it that way too. I don't know what software might be available >for the Thinkpad at that sample rate though. > >The next step in commercial systems looks like a 96kHz sample >rate - if this eventually finds its way into notebook computers >you'd have no trouble at all, but that's probably a year or >two away. > I'm just trying to record a train passing by for a small project, so if I choose 22KHz, is that the sample rate, or the other rate? Or do you think 11KHz might work fine as well? -- Paul Khoury pkhoury@loop.com http://pkhoury.dyn.ml.org (if you can't get to the website, then I'm not online) To request a list of available docuements, reply with DOCUMENTS in the subject line. Current system statistics: The Operating System/2 Version is 4.00 Revision 9.029 There are 22 Processes with 84 Threads. This machine's uptime is 0d 1h 6m 0s 421ms.