From asantos@cam.ac.uk Wed Feb 08 00:05:50 1995 Path: ashpoly!cascade!mxgate!coyoacan!cam!asantos From: asantos@cam.ac.uk (Aiko Santos) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Feb08.000550.6895@cam.ac.uk> Date: Wed, 08 Feb 1995 00:05:50 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk 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. When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization! Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Aiko Santos *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0 From dkowalski@delphi.com Thu Feb 09 13:09:50 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!delphi!dkowalski From: dkowalski@delphi.com (Dong-hyun Kowalski) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Feb09.130950.1052@delphi.com> Date: Thu, 09 Feb 1995 13:09:50 GMT References: <1995Feb08.000550.6895@cam.ac.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Feb08.000550.6895@cam.ac.uk>, asantos@cam.ac.uk (Aiko Santos) 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Dong-hyun Kowalski SupraFAXModem 28.8 @ 14,400 bps "They will send a copy in my place."