From jreyes@earthlink.net Thu Nov 17 22:08:37 1994 Path: ashpoly!cascade!brgate!saturno!earthlink!jreyes From: jreyes@earthlink.net (Jen Reyes) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov17.220837.9630@earthlink.net> Date: Thu, 17 Nov 1994 22:08:37 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.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. 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. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Jen Reyes "They will send a copy in my place." Atari Falcon 030 / AmigaOS 3.1 From msanchez@netcom.com Sat Nov 19 23:57:37 1994 Path: ashpoly!cascade!brgate!saturno!netcom!msanchez From: msanchez@netcom.com (Mathieu Sánchez) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov19.235737.7688@netcom.com> Date: Sat, 19 Nov 1994 23:57:37 GMT References: <1994Nov17.220837.9630@earthlink.net> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1994Nov17.220837.9630@earthlink.net>, jreyes@earthlink.net (Jen Reyes) 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. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. PGP Public key available via finger or upon request. -- === Mathieu Sánchez === Dept of Electrical Engineering, NETCOM On-Line Communication Services "The hatch is open. Is anyone listening?" From jeriksson@kth.se Sun Nov 20 20:53:37 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!kth!jeriksson From: jeriksson@kth.se (Joachim Eriksson) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov20.205337.7113@kth.se> Date: Sun, 20 Nov 1994 20:53:37 GMT References: <1994Nov17.220837.9630@earthlink.net> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1994Nov17.220837.9630@earthlink.net>, jreyes@earthlink.net (Jen Reyes) 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! If you are posting from AOL, please read RFC 1036 before posting again. -- Joachim Eriksson | jeriksson@kth.se PGP Key fingerprint: 4A96 8148 70FD 2CA3 "Keep the channels open." From itanaka@titech.ac.jp Tue Nov 22 16:17:37 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!titech!itanaka From: itanaka@titech.ac.jp (Ines Tanaka) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov22.161737.7919@titech.ac.jp> Date: Tue, 22 Nov 1994 16:17:37 GMT References: <1994Nov17.220837.9630@earthlink.net> <1994Nov20.205337.7113@kth.se> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Nov20.205337.7113@kth.se>, jeriksson@kth.se (Joachim Eriksson) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! > If you are posting from AOL, please read RFC 1036 before posting again. Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image? -- Ines Tanaka "In theory there is no difference between theory and practice." Macintosh IIfx / Linux 1.2.13 From jandersson@uni-hamburg.de Tue Nov 22 23:45:37 1994 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!jandersson From: jandersson@uni-hamburg.de (Joachim Andersson) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov22.234537.6199@uni-hamburg.de> Date: Tue, 22 Nov 1994 23:45:37 GMT References: <1994Nov17.220837.9630@earthlink.net> <1994Nov19.235737.7688@netcom.com> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Nov19.235737.7688@netcom.com>, msanchez@netcom.com (Mathieu Sánchez) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. > PGP Public key available via finger or upon request. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Joachim Andersson Opinions expressed are solely my own and not those of Universität Hamburg Fachbereich Informatik. ------------------------------------------------------------