Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucsd!ginger.acc.com!ivucsb!todd
From: todd@ivucsb.sba.ca.us (Todd Day)
Newsgroups: comp.dsp
Subject: Re: More digital mixer stuff
Message-ID: <1989Oct4.085820.22434@ivucsb.sba.ca.us>
Date: 4 Oct 89 08:58:20 GMT
References: <9238@pyr.gatech.EDU> <7905@microsoft.UUCP> <9247@pyr.gatech.EDU> <1845@draken.nada.kth.se>
Organization: Disillusioned Graduate Hackers, Santa Barbara, CA
Lines: 26

d88-jwa@nada.kth.se (Jon W{tte) writes:

~>>Then, for a digital
~>>sample changing from $8000 to $7FFF, you would first get $0000 on the
~>>DAC output before all the other 15 bits changed to $7FFF.  Ugly and BIG
~>>spike!

~Heard about (a) a latch and (b) an analog filter after the DAC ?
~Wouldn't this take care of such things ? ARE there S/H stages after
~the DAC in good CDs ? I don't think so, but please correct me, if you
~know for * SURE *.

I know all Denon players have them.  I'm certain that just about every
CD player has them.  It wouldn't do any good to build a latch into the
DACs because you would still have the problem of each bit not flipping
at EXACTLY the same time.  An analog filter would not solve the problem
because they would have slew problems when the spikes come through.  This
slewing would produce distortion products at the output, and could never
be filtered out entirely.  Hell, they have enough problems just handling
the staircases!

-- 

Todd Day  |  todd@ivucsb.sba.ca.us  |  ivucsb!todd@anise.acc.com
"Time to eat all your words, swallow your pride, open your eyes."
					-- Tears for Fears