From ysmirnov@hanse.de Sun Apr 28 08:21:30 1996 Path: ashpoly!cascade!mxgate!coyoacan!hanse!ysmirnov From: ysmirnov@hanse.de (Yuki Smirnov) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr28.082130.9250@hanse.de> Date: Sun, 28 Apr 1996 08:21:30 GMT Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Yuki Smirnov SupraFAXModem 28.8 @ ISDN 64k bps "Hold for relay." From bduarte@pacbell.net Mon Apr 29 08:55:30 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!pacbell!bduarte From: bduarte@pacbell.net (Bill Duarte) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr29.085530.3679@pacbell.net> Date: Mon, 29 Apr 1996 08:55:30 GMT References: <1996Apr28.082130.9250@hanse.de> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Apr28.082130.9250@hanse.de>, ysmirnov@hanse.de (Yuki Smirnov) 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. -- Bill Duarte | bduarte@pacbell.net PGP Key fingerprint: 1280 EE5C 1488 10F0 "Keep the channels open."