From asokolov@tum.de Fri Aug 02 16:04:54 1996 Path: ashpoly!cascade!transat!ukc!fennimore!tum!asokolov From: asokolov@tum.de (Astrid Sokolov) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Aug02.160454.4256@tum.de> Date: Fri, 02 Aug 1996 16:04:54 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.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. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. 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? -- Astrid Sokolov Zyxel U-1496E @ ISDN 64k bps "Hardware is temporary. The signal survives." From hmuller@demon.co.uk Sun Aug 04 04:11:54 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!demon!hmuller From: hmuller@demon.co.uk (Hana Müller) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Aug04.041154.9372@demon.co.uk> Date: Sun, 04 Aug 1996 04:11:54 GMT References: <1996Aug02.160454.4256@tum.de> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Aug02.160454.4256@tum.de>, asokolov@tum.de (Astrid Sokolov) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- === Hana Müller === Dept of Electrical Engineering, Demon Internet Services UK "Measuring a record you own is listening, not piracy."