adamdea;629632 Wrote: > As to the second point do read the Pohlmann book as it explains it very > well. The point is the quantisation error is noise if uncorrelated to > signal or distortion if correlated (this is essentially a definitional > proposition; but it coincides with a pyschoacoustical point that random > eror is less annoying than signal related error). At low levels ADC's > quantisation error will for engineering reasons become correlated. > Hence it becomes distortion. A dithered sigbnal not only decorrelates > the error but it makes it possible to decode signal BELOW the lsb for > reasons which are very tricky to understand (but if you imagine a > repetitive sigbnal plus random noise you can see that by stistical > inference you can decode the signal below the noise.) Believe it or not > dither was discovered (not invented) as it naturally occured in WWII > airplane navigation instruments- they worked better (ie more > accurately)in the planes (where there was vibration) than in the lab- > why? because the random vibration decorrelated (and maybe reduced?)the > errors caused by stickiness at the lowest level of reading. > AS for your maths I can;t find a published table to check my reasoning > but I still can't see how distortion is 25% with two bits. The maximum > signal is 3 (11) and the quantisation error is surely still 0.5 at > most.(Help there must be someone clever here who can confirm one way of > the other)
That's correct. The quantisation error (noise) is alawys in the lowest 0.5 bit. -- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... Touch(wired/XP) - Audiolense 3.3/2.0+INGUZ DRC - MF M1 DAC - Linn 5103 - full Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Pekin Tuner, Townsend Supertweeters, Blue Jeans Belden Digital,Kimber 8TC Speaker & Chord Signature Plus Interconnect cables Stax4070+SRM7/II phones Kitchen Boom, Outdoors: SB Radio, Harmony One remote for everything. ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=87175 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
