From koliveira@u-tokyo.ac.jp Fri Dec 22 00:18:22 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!u-tokyo!koliveira From: koliveira@u-tokyo.ac.jp (Katrin Oliveira) Newsgroups: comp.sys.m68k Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Dec22.001822.3988@u-tokyo.ac.jp> Date: Fri, 22 Dec 1995 00:18:22 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 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! -- Katrin Oliveira *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0 From sgonzalez@stanford.edu Fri Dec 22 18:30:22 1995 Path: ashpoly!cascade!brgate!saturno!stanford!sgonzalez From: sgonzalez@stanford.edu (Sun-mi González) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Dec22.183022.2880@stanford.edu> Date: Fri, 22 Dec 1995 18:30:22 GMT References: <1995Dec22.001822.3988@u-tokyo.ac.jp> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec22.001822.3988@u-tokyo.ac.jp>, koliveira@u-tokyo.ac.jp (Katrin Oliveira) 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. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Sun-mi González -- Stanford University Computer Systems Lab "Extraordinary claims require extraordinary spectra."