From rfischer@rwth-aachen.de Tue Aug 08 08:25:09 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!rwth-aachen!rfischer From: rfischer@rwth-aachen.de (Rodrigo Fischer) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug08.082509.4152@rwth-aachen.de> Date: Tue, 08 Aug 1995 08:25:09 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de 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. 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. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Rodrigo Fischer *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From moliveira@pipeline.com Tue Aug 08 16:06:09 1995 Path: ashpoly!cascade!brgate!saturno!pipeline!moliveira From: moliveira@pipeline.com (Min-jun Oliveira) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug08.160609.7906@pipeline.com> Date: Tue, 08 Aug 1995 16:06:09 GMT References: <1995Aug08.082509.4152@rwth-aachen.de> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Aug08.082509.4152@rwth-aachen.de>, rfischer@rwth-aachen.de (Rodrigo Fischer) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Min-jun Oliveira Tape trading list upon request. SASE required for international mail. From hnakamura@pipeline.com Wed Aug 09 01:20:09 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!pipeline!hnakamura From: hnakamura@pipeline.com (Hugo Nakamura) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug09.012009.7734@pipeline.com> Date: Wed, 09 Aug 1995 01:20:09 GMT References: <1995Aug08.082509.4152@rwth-aachen.de> <1995Aug08.160609.7906@pipeline.com> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Aug08.160609.7906@pipeline.com>, moliveira@pipeline.com (Min-jun Oliveira) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Hugo Nakamura *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0