From mcampbell@titech.ac.jp Sun Jun 25 11:31:36 1995
Path: ashpoly!cascade!bigsur!titech!mcampbell
From: mcampbell@titech.ac.jp (Marta Campbell)
Newsgroups: comp.sys.m68k
Subject: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Jun25.113136.4585@titech.ac.jp>
Date: Sun, 25 Jun 1995 11:31:36 GMT
Organization: Tokyo Institute of Technology Computer Centre
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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?

-- 
Marta Campbell
Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre.
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From jsilva@kiae.su Mon Jun 26 15:49:36 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!kiae!jsilva
From: jsilva@kiae.su (Jens Silva)
Newsgroups: comp.sys.m68k
Subject: Re: [FLAME] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Jun26.154936.2040@kiae.su>
Date: Mon, 26 Jun 1995 15:49:36 GMT
References: <1995Jun25.113136.4585@titech.ac.jp>
Organization: Kurchatov Institute of Atomic Energy, Moscow
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In article <1995Jun25.113136.4585@titech.ac.jp>, mcampbell@titech.ac.jp (Marta Campbell) 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.

Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window.

-- 
=== Jens Silva ===
Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow
"Tape doesn't lie at 02:14. Ears do."