From ktakahashi@pacbell.net Sun Mar 12 02:38:44 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!pacbell!ktakahashi From: ktakahashi@pacbell.net (Kenji Takahashi) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Mar12.023844.9808@pacbell.net> Date: Sun, 12 Mar 1995 02:38:44 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Kenji Takahashi *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0 From fpopov@cern.ch Mon Mar 13 07:09:44 1995 Path: ashpoly!cascade!mxgate!coyoacan!cern!fpopov From: fpopov@cern.ch (Freya Popov) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Mar13.070944.6224@cern.ch> Date: Mon, 13 Mar 1995 07:09:44 GMT References: <1995Mar12.023844.9808@pacbell.net> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Mar12.023844.9808@pacbell.net>, ktakahashi@pacbell.net (Kenji Takahashi) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Freya Popov Hayes Optima 288 @ 9600 Telebit bps "When every node is whole, the channel opens." From bgirard@hanse.de Tue Mar 14 21:52:44 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!hanse!bgirard From: bgirard@hanse.de (Bruno Girard) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Mar14.215244.5215@hanse.de> Date: Tue, 14 Mar 1995 21:52:44 GMT References: <1995Mar12.023844.9808@pacbell.net> <1995Mar13.070944.6224@cern.ch> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar13.070944.6224@cern.ch>, fpopov@cern.ch (Freya Popov) writes: > PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Bruno Girard | bgirard@hanse.de PGP Key fingerprint: 082A 7749 80B8 4C7D "Keep the channels open."