From tkim@kth.se Tue Mar 05 02:15:28 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!tkim From: tkim@kth.se (Tyler Kim) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar05.021528.2191@kth.se> Date: Tue, 05 Mar 1996 02:15:28 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N Lines: 11 Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. 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. -- Tyler Kim "When every node is whole, the channel opens." Sun SparcStation 20 / FreeBSD 2.1 From akim@netcom.com Tue Mar 05 21:01:28 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!netcom!akim From: akim@netcom.com (Amy Kim) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar05.210128.8594@netcom.com> Date: Tue, 05 Mar 1996 21:01:28 GMT References: <1996Mar05.021528.2191@kth.se> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1996Mar05.021528.2191@kth.se>, tkim@kth.se (Tyler Kim) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. Top-posters will be placed in my ~/.killfile without notice. -- Amy Kim | akim@netcom.com PGP Key fingerprint: F597 010D C951 0C88 "Keep the channels open." From tpopov@cam.ac.uk Tue Mar 05 22:07:28 1996 Path: ashpoly!cascade!brgate!saturno!cam!tpopov From: tpopov@cam.ac.uk (Tomas Popov) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar05.220728.3790@cam.ac.uk> Date: Tue, 05 Mar 1996 22:07:28 GMT References: <1996Mar05.021528.2191@kth.se> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Mar05.021528.2191@kth.se>, tkim@kth.se (Tyler Kim) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Tomas Popov Hayes Optima 288 @ 19,200 bps "Tape doesn't lie at 02:14. Ears do."