From jmoreau@mit.edu Thu Feb 03 00:53:08 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!jmoreau From: jmoreau@mit.edu (Jen Moreau) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Feb03.005308.1130@mit.edu> Date: Thu, 03 Feb 1994 00:53:08 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 11 Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. 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! -- Jen Moreau Zyxel U-1496E @ 14,400 bps "A soul is not exclusive to biology." From bpopov@kth.se Fri Feb 04 17:07:08 1994 Path: ashpoly!cascade!mxgate!coyoacan!kth!bpopov From: bpopov@kth.se (Bruno Popov) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Feb04.170708.3913@kth.se> Date: Fri, 04 Feb 1994 17:07:08 GMT References: <1994Feb03.005308.1130@mit.edu> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994Feb03.005308.1130@mit.edu>, jmoreau@mit.edu (Jen Moreau) writes: > Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Bruno Popov *PLONK* filter active for trolls. Sun SparcStation 20 - NetBSD 1.0