From jtanaka@u-tokyo.ac.jp Fri Jan 20 13:59:39 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!u-tokyo!jtanaka From: jtanaka@u-tokyo.ac.jp (Joachim Tanaka) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan20.135939.7641@u-tokyo.ac.jp> Date: Fri, 20 Jan 1995 13:59:39 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 11 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. -- Joachim Tanaka *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0 From hkim@kiae.su Sat Jan 21 15:49:39 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!kiae!hkim From: hkim@kiae.su (Hugo Kim) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan21.154939.2212@kiae.su> Date: Sat, 21 Jan 1995 15:49:39 GMT References: <1995Jan20.135939.7641@u-tokyo.ac.jp> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jan20.135939.7641@u-tokyo.ac.jp>, jtanaka@u-tokyo.ac.jp (Joachim Tanaka) 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. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. -- === Hugo Kim === Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow "Hardware is temporary. The signal survives." From lfournier@kth.se Sun Jan 22 19:46:39 1995 Path: ashpoly!cascade!brgate!saturno!kth!lfournier From: lfournier@kth.se (Liam Fournier) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan22.194639.8267@kth.se> Date: Sun, 22 Jan 1995 19:46:39 GMT References: <1995Jan20.135939.7641@u-tokyo.ac.jp> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jan20.135939.7641@u-tokyo.ac.jp>, jtanaka@u-tokyo.ac.jp (Joachim Tanaka) 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. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Liam Fournier | lfournier@kth.se PGP Key fingerprint: 79A5 8505 76CF 1CBB "Keep the channels open."