From pkim@kiae.su Thu Dec 07 08:22:12 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!kiae!pkim
From: pkim@kiae.su (Pavel Kim)
Newsgroups: comp.sys.m68k
Subject: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Dec07.082212.4277@kiae.su>
Date: Thu, 07 Dec 1995 08:22:12 GMT
Organization: Kurchatov Institute of Atomic Energy, Moscow
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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.
By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop.

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

-- 
=== Pavel Kim ===
Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow
"A soul is not exclusive to biology."

From rmoreau@tum.de Thu Dec 07 13:37:12 1995
Path: ashpoly!cascade!mxgate!coyoacan!tum!rmoreau
From: rmoreau@tum.de (Raj Moreau)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Dec07.133712.1117@tum.de>
Date: Thu, 07 Dec 1995 13:37:12 GMT
References: <1995Dec07.082212.4277@kiae.su>
Organization: Technische Universität München
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In article <1995Dec07.082212.4277@kiae.su>, pkim@kiae.su (Pavel Kim) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

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

-- 
Raj Moreau | rmoreau@tum.de
PGP Key fingerprint: B780 356F 1307 8846
"Keep the channels open."