From jtanaka@kth.se Sat Jan 07 19:49:54 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!kth!jtanaka From: jtanaka@kth.se (Julien Tanaka) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan07.194954.9362@kth.se> Date: Sat, 07 Jan 1995 19:49:54 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] 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. 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. -- Julien Tanaka "Marcus is not one man." 486DX2/66 (Linux 1.2.13) / FreeBSD 2.1 From sandersson@pacbell.net Sat Jan 07 21:41:54 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!sandersson From: sandersson@pacbell.net (Sun-mi Andersson) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan07.214154.4665@pacbell.net> Date: Sat, 07 Jan 1995 21:41:54 GMT References: <1995Jan07.194954.9362@kth.se> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jan07.194954.9362@kth.se>, jtanaka@kth.se (Julien Tanaka) 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. -- Sun-mi Andersson | sandersson@pacbell.net PGP Key fingerprint: 596E EE72 B1B1 D177 "Keep the channels open." From dmartinez@stanford.edu Sat Jan 07 22:28:54 1995 Path: ashpoly!cascade!brgate!saturno!stanford!dmartinez From: dmartinez@stanford.edu (Dave Martínez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan07.222854.7784@stanford.edu> Date: Sat, 07 Jan 1995 22:28:54 GMT References: <1995Jan07.194954.9362@kth.se> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jan07.194954.9362@kth.se>, jtanaka@kth.se (Julien Tanaka) 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. -- Dave Martínez Tape trading list upon request. SASE required for international mail. From msmirnov@cam.ac.uk Mon Jan 09 05:26:54 1995 Path: ashpoly!cascade!bigsur!cam!msmirnov From: msmirnov@cam.ac.uk (Mikhail Smirnov) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan09.052654.8568@cam.ac.uk> Date: Mon, 09 Jan 1995 05:26:54 GMT References: <1995Jan07.194954.9362@kth.se> <1995Jan07.214154.4665@pacbell.net> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Jan07.214154.4665@pacbell.net>, sandersson@pacbell.net (Sun-mi Andersson) writes: > Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Mikhail Smirnov | msmirnov@cam.ac.uk PGP Key fingerprint: 4BE4 D3F9 82D2 5E4A "Keep the channels open." From ibrennan@purdue.edu Mon Jan 09 14:43:54 1995 Path: ashpoly!cascade!bigsur!purdue!ibrennan From: ibrennan@purdue.edu (Ines Brennan) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan09.144354.5399@purdue.edu> Date: Mon, 09 Jan 1995 14:43:54 GMT References: <1995Jan07.194954.9362@kth.se> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jan07.194954.9362@kth.se>, jtanaka@kth.se (Julien Tanaka) 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Ines Brennan "When every node is whole, the channel opens." PC-9821Ap2 (NEC) / AmigaOS 3.1