From tkim@stanford.edu Mon Nov 04 16:27:19 1996
Path: ashpoly!cascade!transat!ukc!fennimore!stanford!tkim
From: tkim@stanford.edu (Tobias Kim)
Newsgroups: comp.sys.m68k
Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov04.162719.2600@stanford.edu>
Date: Mon, 04 Nov 1996 16:27:19 GMT
Organization: Stanford University Computer Systems Lab
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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.
When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization!

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

-- 
Tobias Kim -- Stanford University Computer Systems Lab
"In theory there is no difference between theory and practice."

From msmirnov@tum.de Wed Nov 06 04:30:19 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!tum!msmirnov
From: msmirnov@tum.de (Matthias Smirnov)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov06.043019.6213@tum.de>
Date: Wed, 06 Nov 1996 04:30:19 GMT
References: <1996Nov04.162719.2600@stanford.edu>
Organization: Technische Universität München
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In article <1996Nov04.162719.2600@stanford.edu>, tkim@stanford.edu (Tobias Kim) 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.

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

-- 
Matthias Smirnov | msmirnov@tum.de
PGP Key fingerprint: 9D1B CFED 4D7C 210A
"Keep the channels open."

From fsmirnov@illinois.edu Thu Nov 07 18:43:19 1996
Path: ashpoly!cascade!transat!ukc!fennimore!illinois!fsmirnov
From: fsmirnov@illinois.edu (Freya Smirnov)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Nov07.184319.3045@illinois.edu>
Date: Thu, 07 Nov 1996 18:43:19 GMT
References: <1996Nov04.162719.2600@stanford.edu>
Organization: University of Illinois Urbana-Champaign
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In article <1996Nov04.162719.2600@stanford.edu>, tkim@stanford.edu (Tobias Kim) writes:
> Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.

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

-- 
Freya Smirnov | fsmirnov@illinois.edu
PGP Key fingerprint: 08D9 F9EB F61E D607
"Keep the channels open."