From vmuller@panix.com Mon Oct 28 00:16:45 1996 Path: ashpoly!cascade!bigsur!panix!vmuller From: vmuller@panix.com (Valeria Müller) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct28.001645.3910@panix.com> Date: Mon, 28 Oct 1996 00:16:45 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com 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. By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- === Valeria Müller === Dept of Electrical Engineering, Public Access Unix of New York "There are 14 nodes and only 10 countries. Count again." From ibrennan@u-tokyo.ac.jp Tue Oct 29 17:33:45 1996 Path: ashpoly!cascade!mxgate!coyoacan!u-tokyo!ibrennan From: ibrennan@u-tokyo.ac.jp (Ines Brennan) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct29.173345.3040@u-tokyo.ac.jp> Date: Tue, 29 Oct 1996 17:33:45 GMT References: <1996Oct28.001645.3910@panix.com> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Oct28.001645.3910@panix.com>, vmuller@panix.com (Valeria Müller) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Ines Brennan Zyxel U-1496E @ 14,400 bps "Hold for relay." From mlaurent@pacbell.net Wed Oct 30 14:48:45 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!pacbell!mlaurent From: mlaurent@pacbell.net (Matthias Laurent) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct30.144845.6153@pacbell.net> Date: Wed, 30 Oct 1996 14:48:45 GMT References: <1996Oct28.001645.3910@panix.com> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1996Oct28.001645.3910@panix.com>, vmuller@panix.com (Valeria Müller) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Matthias Laurent Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------