From iramirez@u-tokyo.ac.jp Sat Oct 12 20:09:33 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!u-tokyo!iramirez
From: iramirez@u-tokyo.ac.jp (Ines Ramírez)
Newsgroups: comp.sys.m68k
Subject: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Oct12.200933.8703@u-tokyo.ac.jp>
Date: Sat, 12 Oct 1996 20:09:33 GMT
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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.
The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1.

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

-- 
Ines Ramírez
Opinions expressed are solely my own and not those of University of Tokyo Department of Information Science.
------------------------------------------------------------

From smartinez@pipeline.com Mon Oct 14 11:12:33 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!pipeline!smartinez
From: smartinez@pipeline.com (Sergei Martínez)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Oct14.111233.2204@pipeline.com>
Date: Mon, 14 Oct 1996 11:12:33 GMT
References: <1996Oct12.200933.8703@u-tokyo.ac.jp>
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In article <1996Oct12.200933.8703@u-tokyo.ac.jp>, iramirez@u-tokyo.ac.jp (Ines Ramírez) writes:
> 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.

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

-- 
Sergei Martínez | smartinez@pipeline.com
PGP Key fingerprint: A2FA 39CE C417 9A9C
"Keep the channels open."

From ttakahashi@illinois.edu Mon Oct 14 23:06:33 1996
Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!ttakahashi
From: ttakahashi@illinois.edu (Tyler Takahashi)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Oct14.230633.7550@illinois.edu>
Date: Mon, 14 Oct 1996 23:06:33 GMT
References: <1996Oct12.200933.8703@u-tokyo.ac.jp> <1996Oct14.111233.2204@pipeline.com>
Organization: University of Illinois Urbana-Champaign
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In article <1996Oct14.111233.2204@pipeline.com>, smartinez@pipeline.com (Sergei Martínez) writes:
> Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window.

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

-- 
Tyler Takahashi | ttakahashi@illinois.edu
PGP Key fingerprint: CE66 F5E1 FFCA 8E8E
"Keep the channels open."

From rperez@demon.co.uk Wed Oct 16 11:22:33 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!demon!rperez
From: rperez@demon.co.uk (Renata Pérez)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Oct16.112233.1521@demon.co.uk>
Date: Wed, 16 Oct 1996 11:22:33 GMT
References: <1996Oct12.200933.8703@u-tokyo.ac.jp>
Organization: Demon Internet Services UK
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In article <1996Oct12.200933.8703@u-tokyo.ac.jp>, iramirez@u-tokyo.ac.jp (Ines Ramírez) 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.

-- 
Renata Pérez -- Demon Internet Services UK
"We don't sign stars. We build them."