From avasiliev@mindspring.com Thu Mar 09 17:38:11 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!mindspring!avasiliev
From: avasiliev@mindspring.com (Andrei Vasiliev)
Newsgroups: comp.sys.m68k
Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Mar09.173811.1393@mindspring.com>
Date: Thu, 09 Mar 1995 17:38:11 GMT
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Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.

I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz.
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.

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

-- 
Andrei Vasiliev | avasiliev@mindspring.com
PGP Key fingerprint: 8E90 CF79 E9BA 8098
"Keep the channels open."

From ssilva@clari.net Sat Mar 11 05:03:11 1995
Path: ashpoly!cascade!bigsur!clari!ssilva
From: ssilva@clari.net (Sven Silva)
Newsgroups: comp.sys.m68k
Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Mar11.050311.1762@clari.net>
Date: Sat, 11 Mar 1995 05:03:11 GMT
References: <1995Mar09.173811.1393@mindspring.com>
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In article <1995Mar09.173811.1393@mindspring.com>, avasiliev@mindspring.com (Andrei Vasiliev) writes:
> Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler.
> I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz.

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

-- 
Sven Silva
Opinions expressed are solely my own and not those of ClariNet Communications Corp.
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