From abrennan@cmu.edu Thu Aug 15 20:51:32 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!cmu!abrennan From: abrennan@cmu.edu (Amy Brennan) Newsgroups: comp.sys.m68k Subject: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Aug15.205132.2790@cmu.edu> Date: Thu, 15 Aug 1996 20:51:32 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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. -- Amy Brennan Tape trading list upon request. SASE required for international mail. From sandersson@cmu.edu Fri Aug 16 10:47:32 1996 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!sandersson From: sandersson@cmu.edu (Sven Andersson) Newsgroups: comp.sys.m68k Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Aug16.104732.3067@cmu.edu> Date: Fri, 16 Aug 1996 10:47:32 GMT References: <1996Aug15.205132.2790@cmu.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Aug15.205132.2790@cmu.edu>, abrennan@cmu.edu (Amy Brennan) 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. -- Sven Andersson "Measuring a record you own is listening, not piracy." Acorn RiscPC 600 / Linux 1.2.13 From npopov@earthlink.net Sat Aug 17 16:43:32 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!npopov From: npopov@earthlink.net (Natalia Popov) Newsgroups: comp.sys.m68k Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Aug17.164332.9099@earthlink.net> Date: Sat, 17 Aug 1996 16:43:32 GMT References: <1996Aug15.205132.2790@cmu.edu> <1996Aug16.104732.3067@cmu.edu> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Aug16.104732.3067@cmu.edu>, sandersson@cmu.edu (Sven Andersson) writes: > Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- === Natalia Popov === Dept of Electrical Engineering, EarthLink Network "Hold for relay."