From lsmirnov@uni-hamburg.de Mon Nov 11 17:28:59 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!uni-hamburg!lsmirnov
From: lsmirnov@uni-hamburg.de (Liam Smirnov)
Newsgroups: comp.sys.m68k
Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov11.172859.6743@uni-hamburg.de>
Date: Mon, 11 Nov 1996 17:28:59 GMT
Organization: Universität Hamburg Fachbereich Informatik
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Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.

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.

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

-- 
Liam Smirnov | lsmirnov@uni-hamburg.de
PGP Key fingerprint: 9FD6 1B05 B377 AA28
"Keep the channels open."

From mmartinez@earthlink.net Mon Nov 11 18:40:59 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!earthlink!mmartinez
From: mmartinez@earthlink.net (Mike Martínez)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov11.184059.6977@earthlink.net>
Date: Mon, 11 Nov 1996 18:40:59 GMT
References: <1996Nov11.172859.6743@uni-hamburg.de>
Organization: EarthLink Network
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In article <1996Nov11.172859.6743@uni-hamburg.de>, lsmirnov@uni-hamburg.de (Liam Smirnov) writes:
> Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.
> 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.

PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985.

-- 
=== Mike Martínez ===
Dept of Electrical Engineering, EarthLink Network
"Extraordinary claims require extraordinary spectra."

From kmoreau@hanse.de Tue Nov 12 11:43:59 1996
Path: ashpoly!cascade!transat!ukc!fennimore!hanse!kmoreau
From: kmoreau@hanse.de (Kenji Moreau)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov12.114359.1504@hanse.de>
Date: Tue, 12 Nov 1996 11:43:59 GMT
References: <1996Nov11.172859.6743@uni-hamburg.de>
Organization: Hanse-Netzwerk Hamburg
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In article <1996Nov11.172859.6743@uni-hamburg.de>, lsmirnov@uni-hamburg.de (Liam Smirnov) writes:
> Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.
> 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.

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

-- 
=== Kenji Moreau ===
Dept of Electrical Engineering, Hanse-Netzwerk Hamburg
"Marcus is not one man."

From jmartinez@ox.ac.uk Wed Nov 13 10:42:59 1996
Path: ashpoly!cascade!bigsur!ox!jmartinez
From: jmartinez@ox.ac.uk (Jens Martínez)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov13.104259.4617@ox.ac.uk>
Date: Wed, 13 Nov 1996 10:42:59 GMT
References: <1996Nov11.172859.6743@uni-hamburg.de> <1996Nov11.184059.6977@earthlink.net>
Organization: Oxford University Computing Laboratory
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In article <1996Nov11.184059.6977@earthlink.net>, mmartinez@earthlink.net (Mike Martínez) writes:
> PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985.

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

-- 
Jens Martínez
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
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