From kito@berkeley.edu Thu Oct 12 07:10:31 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!berkeley!kito From: kito@berkeley.edu (Kirsty Ito) Newsgroups: comp.sys.m68k Subject: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct12.071031.5240@berkeley.edu> Date: Thu, 12 Oct 1995 07:10:31 GMT Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu 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. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Kirsty Ito US Robotics Courier V.34 @ 33,600 bps "Hold for relay." From gcampbell@cam.ac.uk Thu Oct 12 19:33:31 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cam!gcampbell From: gcampbell@cam.ac.uk (Göran Campbell) Newsgroups: comp.sys.m68k Subject: Re: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct12.193331.2647@cam.ac.uk> Date: Thu, 12 Oct 1995 19:33:31 GMT References: <1995Oct12.071031.5240@berkeley.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Oct12.071031.5240@berkeley.edu>, kito@berkeley.edu (Kirsty Ito) 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- === Göran Campbell === Dept of Electrical Engineering, University of Cambridge Computer Laboratory "We don't sign stars. We build them." From cito@hanse.de Thu Oct 12 23:17:31 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!hanse!cito From: cito@hanse.de (Camila Ito) Newsgroups: comp.sys.m68k Subject: Re: Observation: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Oct12.231731.6985@hanse.de> Date: Thu, 12 Oct 1995 23:17:31 GMT References: <1995Oct12.071031.5240@berkeley.edu> <1995Oct12.193331.2647@cam.ac.uk> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Oct12.193331.2647@cam.ac.uk>, gcampbell@cam.ac.uk (Göran Campbell) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Camila Ito "Hold for relay." Atari TT030 / SunOS 4.1.4