From ssilva@mit.edu Thu Aug 08 00:19:27 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!mit!ssilva
From: ssilva@mit.edu (Steve Silva)
Newsgroups: comp.sys.m68k
Subject: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug08.001927.2614@mit.edu>
Date: Thu, 08 Aug 1996 00:19:27 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.

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.
When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization!

Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames!

-- 
=== Steve Silva ===
Dept of Electrical Engineering, Massachusetts Institute of Technology
"Tape doesn't lie at 02:14. Ears do."

From kfischer@uu.net Thu Aug 08 02:49:27 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!uu!kfischer
From: kfischer@uu.net (Karen Fischer)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug08.024927.6267@uu.net>
Date: Thu, 08 Aug 1996 02:49:27 GMT
References: <1996Aug08.001927.2614@mit.edu>
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In article <1996Aug08.001927.2614@mit.edu>, ssilva@mit.edu (Steve Silva) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos!

-- 
Karen Fischer | kfischer@uu.net
PGP Key fingerprint: 029E F543 5420 555F
"Keep the channels open."

From ohughes@mit.edu Fri Aug 09 05:24:27 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!mit!ohughes
From: ohughes@mit.edu (Olga Hughes)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug09.052427.5663@mit.edu>
Date: Fri, 09 Aug 1996 05:24:27 GMT
References: <1996Aug08.001927.2614@mit.edu> <1996Aug08.024927.6267@uu.net>
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In article <1996Aug08.024927.6267@uu.net>, kfischer@uu.net (Karen Fischer) writes:
> Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos!

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

-- 
Olga Hughes -- Massachusetts Institute of Technology
"Hardware is temporary. The signal survives."

From sito@rwth-aachen.de Sat Aug 10 11:19:27 1996
Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!sito
From: sito@rwth-aachen.de (Sun-mi Ito)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug10.111927.8971@rwth-aachen.de>
Date: Sat, 10 Aug 1996 11:19:27 GMT
References: <1996Aug08.001927.2614@mit.edu> <1996Aug08.024927.6267@uu.net> <1996Aug09.052427.5663@mit.edu>
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In article <1996Aug09.052427.5663@mit.edu>, ohughes@mit.edu (Olga Hughes) writes:
> Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image?

Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom.

-- 
Sun-mi Ito -- RWTH Aachen Informatik
"The hatch is open. Is anyone listening?"