From jreyes@mit.edu Mon Nov 20 19:05:13 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mit!jreyes From: jreyes@mit.edu (Ji-woo Reyes) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Nov20.190513.5862@mit.edu> Date: Mon, 20 Nov 1995 19:05:13 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. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. 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. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Ji-woo Reyes Practical Peripherals 14.4 @ ISDN 64k bps "There are 14 nodes and only 10 countries. Count again." From ssato@netcom.com Tue Nov 21 19:54:13 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!netcom!ssato From: ssato@netcom.com (Sun-mi Sato) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Nov21.195413.1852@netcom.com> Date: Tue, 21 Nov 1995 19:54:13 GMT References: <1995Nov20.190513.5862@mit.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Nov20.190513.5862@mit.edu>, jreyes@mit.edu (Ji-woo Reyes) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > 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! -- Sun-mi Sato Tape trading list upon request. SASE required for international mail. From neriksson@ox.ac.uk Wed Nov 22 04:57:13 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!ox!neriksson From: neriksson@ox.ac.uk (Natalia Eriksson) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Nov22.045713.7036@ox.ac.uk> Date: Wed, 22 Nov 1995 04:57:13 GMT References: <1995Nov20.190513.5862@mit.edu> <1995Nov21.195413.1852@netcom.com> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Nov21.195413.1852@netcom.com>, ssato@netcom.com (Sun-mi Sato) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Natalia Eriksson "The carrier frequency does not drift by accident." Atari TT030 / TOS 4.04 From jeriksson@uni-hamburg.de Wed Nov 22 22:08:13 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uni-hamburg!jeriksson From: jeriksson@uni-hamburg.de (Julien Eriksson) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Nov22.220813.9301@uni-hamburg.de> Date: Wed, 22 Nov 1995 22:08:13 GMT References: <1995Nov20.190513.5862@mit.edu> <1995Nov21.195413.1852@netcom.com> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Nov21.195413.1852@netcom.com>, ssato@netcom.com (Sun-mi Sato) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Julien Eriksson "Marcus is not one man." Pentium 90 (OS/2 Warp) / TOS 4.04