From ibrennan@earthlink.net Tue Dec 27 21:16:42 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!earthlink!ibrennan From: ibrennan@earthlink.net (Ines Brennan) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Dec27.211642.2558@earthlink.net> Date: Tue, 27 Dec 1994 21:16:42 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.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. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Ines Brennan "Do not worship the copy." Amiga 3000T / TOS 4.04 From feriksson@demon.co.uk Wed Dec 28 10:37:42 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!demon!feriksson From: feriksson@demon.co.uk (Freya Eriksson) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Dec28.103742.3711@demon.co.uk> Date: Wed, 28 Dec 1994 10:37:42 GMT References: <1994Dec27.211642.2558@earthlink.net> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Dec27.211642.2558@earthlink.net>, ibrennan@earthlink.net (Ines Brennan) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- === Freya Eriksson === Dept of Electrical Engineering, Demon Internet Services UK "Row 14. No joke."