Path: utzoo!attcan!uunet!portal!cup.portal.com!doug-merritt
From: doug-merritt@cup.portal.com
Newsgroups: comp.sys.amiga
Subject: Re: Sampling at 29KHz (long)
Message-ID: <5912@cup.portal.com>
Date: 25 May 88 22:14:11 GMT
References: <2845@polya.STANFORD.EDU> <734@eos.UUCP> <53788@sun.uucp> <5637@cup.portal.com> <765@eos.UUCP>
Organization: The Portal System (TM)
Lines: 33
XPortal-User-Id: 1.1001.4407

Phil Stone wrote:
>....Doug Merritt explains some interesting ways of avoiding sampling
>aliasing using random fluctuations in sampling frequency.... [...]
>Your suggestions on direct (non-DMA) access of the sound device are,
>once again, wonderful from a theoretical point of view, but would drain
>so much CPU time as to make the Amiga difficult to use for other tasks

Totally agree. Do you know whether my idea about doing the same technique
via DMA (period modulation of another channel) would work?

>But to say that it [ the Amiga audio driver ] has *no problems*, even if
>you back this up with a ream of sampling theory, is pure defensiveism. 

Once again, totally agree. Good point. Sorry to have implied otherwise.

>Never thought suggestions for improvement were unwelcome here, Doug.

Oops! Sorry! I take it back, by all means, please do continue making
suggestions for improvements, they're more than welcome!

I meant only to rebut your criticism of Tom, not to flame you!

Actually I'd say that your ideas about fractional period support sound
very useful. As I think you implied, they may require actual hardware
support in a future system rather than just a driver change.

And while we're asking for 4K by 4K by 24 screens :-) why not ask for a
44Khz sampling rate, too? Only half kidding. Some day.
	Doug
--
      Doug Merritt        ucbvax!sun.com!cup.portal.com!doug-merritt
                      or  ucbvax!eris!doug (doug@eris.berkeley.edu)
                      or  ucbvax!unisoft!certes!doug