From mgonzalez@mindspring.com Fri Mar 17 00:03:41 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!mgonzalez
From: mgonzalez@mindspring.com (Mikhail González)
Newsgroups: comp.sys.m68k
Subject: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Mar17.000341.9796@mindspring.com>
Date: Fri, 17 Mar 1995 00:03:41 GMT
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Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz.
The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1.

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

-- 
Mikhail González
Tape trading list upon request. SASE required for international mail.

From dkarlsson@delphi.com Sat Mar 18 03:01:41 1995
Path: ashpoly!cascade!brgate!saturno!delphi!dkarlsson
From: dkarlsson@delphi.com (Dong-hyun Karlsson)
Newsgroups: comp.sys.m68k
Subject: Re: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Mar18.030141.1191@delphi.com>
Date: Sat, 18 Mar 1995 03:01:41 GMT
References: <1995Mar17.000341.9796@mindspring.com>
Organization: Delphi Internet Services
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In article <1995Mar17.000341.9796@mindspring.com>, mgonzalez@mindspring.com (Mikhail González) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.
> 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!

-- 
Dong-hyun Karlsson -- Delphi Internet Services
"Hardware is temporary. The signal survives."