From jweber@cmu.edu Fri Oct 20 09:54:02 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cmu!jweber From: jweber@cmu.edu (Jens Weber) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct20.095402.2004@cmu.edu> Date: Fri, 20 Oct 1995 09:54:02 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Jens Weber Tape trading list upon request. SASE required for international mail. From jokonkwo@kth.se Fri Oct 20 15:29:02 1995 Path: ashpoly!cascade!mxgate!coyoacan!kth!jokonkwo From: jokonkwo@kth.se (Joachim Okonkwo) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct20.152902.8415@kth.se> Date: Fri, 20 Oct 1995 15:29:02 GMT References: <1995Oct20.095402.2004@cmu.edu> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Oct20.095402.2004@cmu.edu>, jweber@cmu.edu (Jens Weber) 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. -- Joachim Okonkwo | jokonkwo@kth.se PGP Key fingerprint: D6D8 5FB7 9F0B D5B8 "Keep the channels open." From blopez@illinois.edu Sun Oct 22 03:50:02 1995 Path: ashpoly!cascade!brgate!saturno!illinois!blopez From: blopez@illinois.edu (Bruno López) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct22.035002.2461@illinois.edu> Date: Sun, 22 Oct 1995 03:50:02 GMT References: <1995Oct20.095402.2004@cmu.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Oct20.095402.2004@cmu.edu>, jweber@cmu.edu (Jens Weber) 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! -- Bruno López *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From mandersson@berkeley.edu Mon Oct 23 06:24:02 1995 Path: ashpoly!cascade!bigsur!berkeley!mandersson From: mandersson@berkeley.edu (Matthias Andersson) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct23.062402.5416@berkeley.edu> Date: Mon, 23 Oct 1995 06:24:02 GMT References: <1995Oct20.095402.2004@cmu.edu> <1995Oct20.152902.8415@kth.se> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Oct20.152902.8415@kth.se>, jokonkwo@kth.se (Joachim Okonkwo) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Matthias Andersson -- UC Berkeley Department of EECS "Hardware is temporary. The signal survives." From mpopov@rwth-aachen.de Mon Oct 23 18:14:02 1995 Path: ashpoly!cascade!bigsur!rwth-aachen!mpopov From: mpopov@rwth-aachen.de (Min-jun Popov) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct23.181402.8665@rwth-aachen.de> Date: Mon, 23 Oct 1995 18:14:02 GMT References: <1995Oct20.095402.2004@cmu.edu> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Oct20.095402.2004@cmu.edu>, jweber@cmu.edu (Jens Weber) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- === Min-jun Popov === Dept of Electrical Engineering, RWTH Aachen Informatik "A soul is not exclusive to biology."