From agarcia@demon.co.uk Fri Apr 14 13:48:56 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!demon!agarcia From: agarcia@demon.co.uk (Astrid García) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Apr14.134856.2670@demon.co.uk> Date: Fri, 14 Apr 1995 13:48:56 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk 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. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. 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. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Astrid García | agarcia@demon.co.uk PGP Key fingerprint: F31F BE2A A19E 0DFE "Keep the channels open." From ksouza@berkeley.edu Sat Apr 15 01:29:56 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!berkeley!ksouza From: ksouza@berkeley.edu (Karen Souza) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Apr15.012956.5528@berkeley.edu> Date: Sat, 15 Apr 1995 01:29:56 GMT References: <1995Apr14.134856.2670@demon.co.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Apr14.134856.2670@demon.co.uk>, agarcia@demon.co.uk (Astrid García) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Karen Souza | ksouza@berkeley.edu PGP Key fingerprint: EF77 0C68 5408 D5E6 "Keep the channels open." From asanchez@tum.de Sun Apr 16 10:47:56 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!tum!asanchez From: asanchez@tum.de (Astrid Sánchez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Apr16.104756.7439@tum.de> Date: Sun, 16 Apr 1995 10:47:56 GMT References: <1995Apr14.134856.2670@demon.co.uk> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Apr14.134856.2670@demon.co.uk>, agarcia@demon.co.uk (Astrid García) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Astrid Sánchez *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0