From asmirnov@uni-hamburg.de Tue Dec 19 22:07:18 1995 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!asmirnov From: asmirnov@uni-hamburg.de (Amy Smirnov) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Dec19.220718.9613@uni-hamburg.de> Date: Tue, 19 Dec 1995 22:07:18 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 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. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Amy Smirnov *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0 From bkowalski@uu.net Thu Dec 21 00:52:18 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!bkowalski From: bkowalski@uu.net (Bastien Kowalski) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Dec21.005218.8861@uu.net> Date: Thu, 21 Dec 1995 00:52:18 GMT References: <1995Dec19.220718.9613@uni-hamburg.de> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Dec19.220718.9613@uni-hamburg.de>, asmirnov@uni-hamburg.de (Amy Smirnov) 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. -- Bastien Kowalski "Extraordinary claims require extraordinary spectra." Pentium 90 (OS/2 Warp) / TOS 4.04