From mnakamura@u-tokyo.ac.jp Tue Sep 05 05:51:30 1995 Path: ashpoly!cascade!brgate!saturno!u-tokyo!mnakamura From: mnakamura@u-tokyo.ac.jp (Matthias Nakamura) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Sep05.055130.2305@u-tokyo.ac.jp> Date: Tue, 05 Sep 1995 05:51:30 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] 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! -- === Matthias Nakamura === Dept of Electrical Engineering, University of Tokyo Department of Information Science "The carrier frequency does not drift by accident." From sgarcia@clari.net Tue Sep 05 13:48:30 1995 Path: ashpoly!cascade!transat!ukc!fennimore!clari!sgarcia From: sgarcia@clari.net (Steve García) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Sep05.134830.8490@clari.net> Date: Tue, 05 Sep 1995 13:48:30 GMT References: <1995Sep05.055130.2305@u-tokyo.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep05.055130.2305@u-tokyo.ac.jp>, mnakamura@u-tokyo.ac.jp (Matthias Nakamura) 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. -- Steve García *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0