cliveb;503336 Wrote: > They seem to have become so of late. > > Back in the Good Olde Days(tm), oversampling meant something very > specific: the stuffing of extra samples into the data stream in order to > move the aliasing artefacts to higher frequencies, so that the > subsequent reconstruction filters have an easier job of removing them. > It doesn't matter what sample values are added (different sample values > will change the nature of the artefacts, but since we're going to be > removing them that's unimportant). Therefore oversamplers typically just > add zeros. Oversamplers always do so by a factor of 2 (ie. they > oversample by 2x, 4x, 8x, 16x, etc). > > OTOH, my understanding is that upsamplers tend to "invent" extra data > values. The marketing departments typically refer to this as a way of > "smoothing out" the signal, which of course is BS since the > reconstruction filter in all DACs does precisely that. And of course > it's impossible to know whether the extra data is anything like what the > original signal might have been before it was bandwidth limited, > although pragmatically you could argue that interpolations might be a > fair approximation. If you then retain this data all the way to the > analogue output (ie. you don't then remove it with the reconstruction > filter), it strikes me that what you end up with is the original in-band > signal plus some additional high frequencies which may or may not bear > some vague similarity to whatever original signal was present prior to > A/D conversion. (Perhaps you can tell that I'm skeptical about the value > of upsampling :-).
Our understandings converge... -- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... SB Touch Beta (wired) - TACT 2.2X (Linear PSU) + Good Vibrations S/W - MF Triplethreat(Audiocom full mods) - Linn 5103 - Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Townsend Supertweeters, Blue Jeans Digital,Kimber Speaker & Chord Interconnect cables Kitchen Boom, Outdoors: SB Radio ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=69145 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
