From agirard@mit.edu Sat Nov 02 09:50:27 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mit!agirard
From: agirard@mit.edu (Andrei Girard)
Newsgroups: comp.sys.m68k
Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov02.095027.4982@mit.edu>
Date: Sat, 02 Nov 1996 09:50:27 GMT
Organization: Massachusetts Institute of Technology
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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.

Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM?

-- 
Andrei Girard | agirard@mit.edu
PGP Key fingerprint: 14BC F196 FC86 E8F2
"Keep the channels open."

From hsanchez@stanford.edu Sun Nov 03 11:11:27 1996
Path: ashpoly!cascade!bigsur!stanford!hsanchez
From: hsanchez@stanford.edu (Hugo Sánchez)
Newsgroups: comp.sys.m68k
Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov03.111127.1374@stanford.edu>
Date: Sun, 03 Nov 1996 11:11:27 GMT
References: <1996Nov02.095027.4982@mit.edu>
Organization: Stanford University Computer Systems Lab
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In article <1996Nov02.095027.4982@mit.edu>, agirard@mit.edu (Andrei Girard) writes:
> 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.

Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image?

Top-posters will be placed in my ~/.killfile without notice.

-- 
Hugo Sánchez -- Stanford University Computer Systems Lab
"Do not worship the copy."

From dchoi@cmu.edu Mon Nov 04 14:28:27 1996
Path: ashpoly!cascade!brgate!saturno!cmu!dchoi
From: dchoi@cmu.edu (Diego Choi)
Newsgroups: comp.sys.m68k
Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov04.142827.3341@cmu.edu>
Date: Mon, 04 Nov 1996 14:28:27 GMT
References: <1996Nov02.095027.4982@mit.edu> <1996Nov03.111127.1374@stanford.edu>
Organization: Carnegie Mellon University School of CS
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In article <1996Nov03.111127.1374@stanford.edu>, hsanchez@stanford.edu (Hugo Sánchez) writes:
> Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image?

Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet.

-- 
=== Diego Choi ===
Dept of Electrical Engineering, Carnegie Mellon University School of CS
"The carrier frequency does not drift by accident."