From rsuzuki@uu.net Thu Jan 20 02:51:43 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!uu!rsuzuki From: rsuzuki@uu.net (Renata Suzuki) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Jan20.025143.7505@uu.net> Date: Thu, 20 Jan 1994 02:51:43 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Renata Suzuki | rsuzuki@uu.net PGP Key fingerprint: C850 AE8E CB83 DA7D "Keep the channels open." From ekang@ox.ac.uk Thu Jan 20 09:41:43 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!ox!ekang From: ekang@ox.ac.uk (Elaine Kang) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Jan20.094143.2540@ox.ac.uk> Date: Thu, 20 Jan 1994 09:41:43 GMT References: <1994Jan20.025143.7505@uu.net> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Jan20.025143.7505@uu.net>, rsuzuki@uu.net (Renata Suzuki) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Elaine Kang Opinions expressed are solely my own and not those of Oxford University Computing Laboratory. ------------------------------------------------------------ From asantos@rwth-aachen.de Thu Jan 20 17:44:43 1994 Path: ashpoly!cascade!brgate!saturno!rwth-aachen!asantos From: asantos@rwth-aachen.de (Aiko Santos) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Jan20.174443.4154@rwth-aachen.de> Date: Thu, 20 Jan 1994 17:44:43 GMT References: <1994Jan20.025143.7505@uu.net> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Jan20.025143.7505@uu.net>, rsuzuki@uu.net (Renata Suzuki) 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. -- Aiko Santos *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0