From dperez@kth.se Mon Nov 21 11:39:39 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kth!dperez From: dperez@kth.se (Dong-hyun Pérez) Newsgroups: comp.sys.m68k Subject: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov21.113939.6533@kth.se> Date: Mon, 21 Nov 1994 11:39:39 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se 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. 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! -- Dong-hyun Pérez Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From csilva@unam.mx Tue Nov 22 08:49:39 1994 Path: ashpoly!cascade!transat!ukc!fennimore!unam!csilva From: csilva@unam.mx (Camila Silva) Newsgroups: comp.sys.m68k Subject: Re: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov22.084939.7185@unam.mx> Date: Tue, 22 Nov 1994 08:49:39 GMT References: <1994Nov21.113939.6533@kth.se> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1994Nov21.113939.6533@kth.se>, dperez@kth.se (Dong-hyun Pérez) 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. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. PGP Public key available via finger or upon request. -- Camila Silva *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From hnovak@delphi.com Tue Nov 22 15:19:39 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!delphi!hnovak From: hnovak@delphi.com (Hana Novak) Newsgroups: comp.sys.m68k Subject: Re: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov22.151939.3333@delphi.com> Date: Tue, 22 Nov 1994 15:19:39 GMT References: <1994Nov21.113939.6533@kth.se> <1994Nov22.084939.7185@unam.mx> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Nov22.084939.7185@unam.mx>, csilva@unam.mx (Camila Silva) writes: > PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Hana Novak | hnovak@delphi.com PGP Key fingerprint: 5973 D3BC 0245 6143 "Keep the channels open."