From lsanchez@earthlink.net Thu Aug 15 01:18:26 1996
Path: ashpoly!cascade!bigsur!earthlink!lsanchez
From: lsanchez@earthlink.net (Lisa Sánchez)
Newsgroups: comp.sys.m68k
Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug15.011826.3884@earthlink.net>
Date: Thu, 15 Aug 1996 01:18:26 GMT
Organization: EarthLink Network
NNTP-Posting-Host: earthlink.net
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Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1.
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?

-- 
Lisa Sánchez
Tape trading list upon request. SASE required for international mail.

From dfischer@inria.fr Thu Aug 15 10:52:26 1996
Path: ashpoly!cascade!mxgate!coyoacan!inria!dfischer
From: dfischer@inria.fr (Dave Fischer)
Newsgroups: comp.sys.m68k
Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1996Aug15.105226.8256@inria.fr>
Date: Thu, 15 Aug 1996 10:52:26 GMT
References: <1996Aug15.011826.3884@earthlink.net>
Organization: INRIA Rocquencourt
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In article <1996Aug15.011826.3884@earthlink.net>, lsanchez@earthlink.net (Lisa Sánchez) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.
> The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1.

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

-- 
Dave Fischer
Opinions expressed are solely my own and not those of INRIA Rocquencourt.
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