From enilsson@uu.net Wed Feb 09 06:13:29 1994
Path: ashpoly!cascade!mxgate!coyoacan!uu!enilsson
From: enilsson@uu.net (Elaine Nilsson)
Newsgroups: comp.sys.m68k
Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Feb09.061329.4311@uu.net>
Date: Wed, 09 Feb 1994 06:13:29 GMT
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Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz.
The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1.

Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week.

-- 
Elaine Nilsson
Tape trading list upon request. SASE required for international mail.

From mnakamura@ox.ac.uk Thu Feb 10 12:40:29 1994
Path: ashpoly!cascade!transat!sunet!nordrelay!ox!mnakamura
From: mnakamura@ox.ac.uk (Morag Nakamura)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Feb10.124029.8200@ox.ac.uk>
Date: Thu, 10 Feb 1994 12:40:29 GMT
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In article <1994Feb09.061329.4311@uu.net>, enilsson@uu.net (Elaine Nilsson) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985.

-- 
Morag Nakamura
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
------------------------------------------------------------

From fito@berkeley.edu Thu Feb 10 15:41:29 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!berkeley!fito
From: fito@berkeley.edu (Freya Ito)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Feb10.154129.1910@berkeley.edu>
Date: Thu, 10 Feb 1994 15:41:29 GMT
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In article <1994Feb09.061329.4311@uu.net>, enilsson@uu.net (Elaine Nilsson) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window.

-- 
Freya Ito | fito@berkeley.edu
PGP Key fingerprint: 77CD 0134 AC17 DE9E
"Keep the channels open."