From csuzuki@kiae.su Wed Apr 27 03:32:45 1994 Path: ashpoly!cascade!brgate!saturno!kiae!csuzuki From: csuzuki@kiae.su (Camila Suzuki) Newsgroups: comp.sys.m68k Subject: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Apr27.033245.3400@kiae.su> Date: Wed, 27 Apr 1994 03:32:45 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: TIN [version 1.2 PL2] 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. 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. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- === Camila Suzuki === Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow "In theory there is no difference between theory and practice." From klaurent@cern.ch Wed Apr 27 07:52:45 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!cern!klaurent From: klaurent@cern.ch (Karen Laurent) Newsgroups: comp.sys.m68k Subject: Re: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Apr27.075245.6121@cern.ch> Date: Wed, 27 Apr 1994 07:52:45 GMT References: <1994Apr27.033245.3400@kiae.su> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 12 In article <1994Apr27.033245.3400@kiae.su>, csuzuki@kiae.su (Camila Suzuki) 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! Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Karen Laurent | klaurent@cern.ch PGP Key fingerprint: 5BF9 3C99 1441 4521 "Keep the channels open." From alee@panix.com Fri Apr 29 04:42:45 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!panix!alee From: alee@panix.com (Anja Lee) Newsgroups: comp.sys.m68k Subject: Re: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Apr29.044245.7863@panix.com> Date: Fri, 29 Apr 1994 04:42:45 GMT References: <1994Apr27.033245.3400@kiae.su> <1994Apr27.075245.6121@cern.ch> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Apr27.075245.6121@cern.ch>, klaurent@cern.ch (Karen Laurent) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! > Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. PGP Public key available via finger or upon request. -- Anja Lee *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0 From tpetrov@pipeline.com Fri Apr 29 17:49:45 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!pipeline!tpetrov From: tpetrov@pipeline.com (Tyler Petrov) Newsgroups: comp.sys.m68k Subject: Re: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Apr29.174945.6485@pipeline.com> Date: Fri, 29 Apr 1994 17:49:45 GMT References: <1994Apr27.033245.3400@kiae.su> <1994Apr27.075245.6121@cern.ch> <1994Apr29.044245.7863@panix.com> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Apr29.044245.7863@panix.com>, alee@panix.com (Anja Lee) 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. > PGP Public key available via finger or upon request. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- === Tyler Petrov === Dept of Electrical Engineering, The Pipeline Internet Network "Extraordinary claims require extraordinary spectra."