From tduarte@uu.net Sat Jan 07 20:04:08 1995 Path: ashpoly!cascade!bigsur!uu!tduarte From: tduarte@uu.net (Thiago Duarte) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan07.200408.3642@uu.net> Date: Sat, 07 Jan 1995 20:04:08 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: Netscape 1.1N Lines: 11 Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. 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 Duarte *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0 From fbrennan@clari.net Sun Jan 08 23:21:08 1995 Path: ashpoly!cascade!mxgate!coyoacan!clari!fbrennan From: fbrennan@clari.net (Freya Brennan) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan08.232108.9469@clari.net> Date: Sun, 08 Jan 1995 23:21:08 GMT References: <1995Jan07.200408.3642@uu.net> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jan07.200408.3642@uu.net>, tduarte@uu.net (Thiago Duarte) writes: > Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. > 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. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Freya Brennan | fbrennan@clari.net PGP Key fingerprint: 4CA9 D546 2364 81D9 "Keep the channels open." From tduarte@kth.se Tue Jan 10 17:10:08 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!kth!tduarte From: tduarte@kth.se (Takeshi Duarte) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan10.171008.5086@kth.se> Date: Tue, 10 Jan 1995 17:10:08 GMT References: <1995Jan07.200408.3642@uu.net> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jan07.200408.3642@uu.net>, tduarte@uu.net (Thiago Duarte) writes: > Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. > 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. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. -- Takeshi Duarte | tduarte@kth.se PGP Key fingerprint: DE14 45B8 2522 3F65 "Keep the channels open."