From tgirard@demon.co.uk Thu Oct 26 16:21:29 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!demon!tgirard From: tgirard@demon.co.uk (Thiago Girard) Newsgroups: comp.sys.m68k Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct26.162129.6973@demon.co.uk> Date: Thu, 26 Oct 1995 16:21:29 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 11 Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. 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! -- Thiago Girard *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From cokonkwo@pipeline.com Sat Oct 28 14:18:29 1995 Path: ashpoly!cascade!mxgate!coyoacan!pipeline!cokonkwo From: cokonkwo@pipeline.com (Callum Okonkwo) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct28.141829.8133@pipeline.com> Date: Sat, 28 Oct 1995 14:18:29 GMT References: <1995Oct26.162129.6973@demon.co.uk> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Oct26.162129.6973@demon.co.uk>, tgirard@demon.co.uk (Thiago Girard) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Callum Okonkwo *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From lhughes@inria.fr Sun Oct 29 05:37:29 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!inria!lhughes From: lhughes@inria.fr (Liam Hughes) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct29.053729.6743@inria.fr> Date: Sun, 29 Oct 1995 05:37:29 GMT References: <1995Oct26.162129.6973@demon.co.uk> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Oct26.162129.6973@demon.co.uk>, tgirard@demon.co.uk (Thiago Girard) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Liam Hughes *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0