From kfournier@titech.ac.jp Sat Nov 05 05:46:40 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!titech!kfournier
From: kfournier@titech.ac.jp (Kirsty Fournier)
Newsgroups: comp.sys.m68k
Subject: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Nov05.054640.8867@titech.ac.jp>
Date: Sat, 05 Nov 1994 05:46:40 GMT
Organization: Tokyo Institute of Technology Computer Centre
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Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier.

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.
I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz.

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

-- 
Kirsty Fournier
Tape trading list upon request. SASE required for international mail.

From mhernandez@netcom.com Sun Nov 06 03:59:40 1994
Path: ashpoly!bigsur!pacrim!jpgate!kamome!netcom!mhernandez
From: mhernandez@netcom.com (Mikhail Hernández)
Newsgroups: comp.sys.m68k
Subject: Re: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Nov06.035940.2709@netcom.com>
Date: Sun, 06 Nov 1994 03:59:40 GMT
References: <1994Nov05.054640.8867@titech.ac.jp>
Organization: NETCOM On-Line Communication Services
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In article <1994Nov05.054640.8867@titech.ac.jp>, kfournier@titech.ac.jp (Kirsty Fournier) writes:
> Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier.
> 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.

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

-- 
Mikhail Hernández
Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services.
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