From mmartinez@mit.edu Thu Aug 25 20:35:40 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mit!mmartinez From: mmartinez@mit.edu (Mike Martínez) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Aug25.203540.7623@mit.edu> Date: Thu, 25 Aug 1994 20:35:40 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Mike Martínez "The hatch is open. Is anyone listening?" Amiga 3000T / NEXTSTEP 3.3 From fdubois@demon.co.uk Sat Aug 27 02:32:40 1994 Path: ashpoly!cascade!mxgate!coyoacan!demon!fdubois From: fdubois@demon.co.uk (Fiona Dubois) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Aug27.023240.2838@demon.co.uk> Date: Sat, 27 Aug 1994 02:32:40 GMT References: <1994Aug25.203540.7623@mit.edu> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1994Aug25.203540.7623@mit.edu>, mmartinez@mit.edu (Mike Martínez) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Fiona Dubois "Do not worship the copy." NeXTstation Turbo Color / TOS 4.04 From jreyes@u-tokyo.ac.jp Sat Aug 27 15:48:40 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!u-tokyo!jreyes From: jreyes@u-tokyo.ac.jp (Jens Reyes) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Aug27.154840.6652@u-tokyo.ac.jp> Date: Sat, 27 Aug 1994 15:48:40 GMT References: <1994Aug25.203540.7623@mit.edu> <1994Aug27.023240.2838@demon.co.uk> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994Aug27.023240.2838@demon.co.uk>, fdubois@demon.co.uk (Fiona Dubois) writes: > Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. > Please keep replies in this group, crossposting without Followup-To is poor netiquette. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- === Jens Reyes === Dept of Electrical Engineering, University of Tokyo Department of Information Science "Measuring a record you own is listening, not piracy." From cpetrov@uu.net Mon Aug 29 11:47:40 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!cpetrov From: cpetrov@uu.net (Camila Petrov) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Aug29.114740.4989@uu.net> Date: Mon, 29 Aug 1994 11:47:40 GMT References: <1994Aug25.203540.7623@mit.edu> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Aug25.203540.7623@mit.edu>, mmartinez@mit.edu (Mike Martínez) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Camila Petrov Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA. ------------------------------------------------------------