From ltakahashi@pacbell.net Fri May 05 11:49:52 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!pacbell!ltakahashi From: ltakahashi@pacbell.net (Lars Takahashi) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995May05.114952.8127@pacbell.net> Date: Fri, 05 May 1995 11:49:52 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 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? -- Lars Takahashi US Robotics Courier V.34 @ ISDN 64k bps "Tape doesn't lie at 02:14. Ears do." From ewatanabe@titech.ac.jp Sat May 06 10:44:52 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!titech!ewatanabe From: ewatanabe@titech.ac.jp (Elaine Watanabe) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995May06.104452.2728@titech.ac.jp> Date: Sat, 06 May 1995 10:44:52 GMT References: <1995May05.114952.8127@pacbell.net> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 12 In article <1995May05.114952.8127@pacbell.net>, ltakahashi@pacbell.net (Lars Takahashi) 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! Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Elaine Watanabe Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre. ------------------------------------------------------------ From npopov@pacbell.net Mon May 08 05:21:52 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!pacbell!npopov From: npopov@pacbell.net (Nadine Popov) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995May08.052152.6160@pacbell.net> Date: Mon, 08 May 1995 05:21:52 GMT References: <1995May05.114952.8127@pacbell.net> <1995May06.104452.2728@titech.ac.jp> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995May06.104452.2728@titech.ac.jp>, ewatanabe@titech.ac.jp (Elaine Watanabe) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. -- === Nadine Popov === Dept of Electrical Engineering, Pacific Bell Internet Services "Tape doesn't lie at 02:14. Ears do." From lchoi@earthlink.net Mon May 08 11:55:52 1995 Path: ashpoly!cascade!bigsur!earthlink!lchoi From: lchoi@earthlink.net (Liam Choi) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995May08.115552.1557@earthlink.net> Date: Mon, 08 May 1995 11:55:52 GMT References: <1995May05.114952.8127@pacbell.net> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995May05.114952.8127@pacbell.net>, ltakahashi@pacbell.net (Lars Takahashi) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Liam Choi *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0