From skang@tum.de Tue Nov 12 01:29:16 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!tum!skang From: skang@tum.de (Sergei Kang) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Nov12.012916.5471@tum.de> Date: Tue, 12 Nov 1996 01:29:16 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. 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. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Sergei Kang | skang@tum.de PGP Key fingerprint: 9CA7 E9B0 E114 9521 "Keep the channels open." From ssanchez@cern.ch Tue Nov 12 18:29:16 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!cern!ssanchez From: ssanchez@cern.ch (Sergei Sánchez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Nov12.182916.9210@cern.ch> Date: Tue, 12 Nov 1996 18:29:16 GMT References: <1996Nov12.012916.5471@tum.de> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Nov12.012916.5471@tum.de>, skang@tum.de (Sergei Kang) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > 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. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Sergei Sánchez Opinions expressed are solely my own and not those of European Laboratory for Particle Physics, Geneva. ------------------------------------------------------------ From trodriguez@u-tokyo.ac.jp Wed Nov 13 12:37:16 1996 Path: ashpoly!cascade!mxgate!coyoacan!u-tokyo!trodriguez From: trodriguez@u-tokyo.ac.jp (Tobias Rodríguez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Nov13.123716.5334@u-tokyo.ac.jp> Date: Wed, 13 Nov 1996 12:37:16 GMT References: <1996Nov12.012916.5471@tum.de> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Nov12.012916.5471@tum.de>, skang@tum.de (Sergei Kang) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > 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. -- Tobias Rodríguez *PLONK* filter active for trolls. Sun SparcStation 20 - NetBSD 1.0 From krobertson@purdue.edu Fri Nov 15 05:39:16 1996 Path: ashpoly!cascade!brgate!saturno!purdue!krobertson From: krobertson@purdue.edu (Kenji Robertson) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Nov15.053916.2761@purdue.edu> Date: Fri, 15 Nov 1996 05:39:16 GMT References: <1996Nov12.012916.5471@tum.de> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Nov12.012916.5471@tum.de>, skang@tum.de (Sergei Kang) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- === Kenji Robertson === Dept of Electrical Engineering, Purdue University Engineering Computer Network "Hold for relay." From mramirez@demon.co.uk Sat Nov 16 18:04:16 1996 Path: ashpoly!cascade!transat!ukc!fennimore!demon!mramirez From: mramirez@demon.co.uk (Mei Ramírez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Nov16.180416.4071@demon.co.uk> Date: Sat, 16 Nov 1996 18:04:16 GMT References: <1996Nov12.012916.5471@tum.de> <1996Nov12.182916.9210@cern.ch> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1996Nov12.182916.9210@cern.ch>, ssanchez@cern.ch (Sergei Sánchez) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image? Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- === Mei Ramírez === Dept of Electrical Engineering, Demon Internet Services UK "The carrier frequency does not drift by accident."