From ttanaka@stanford.edu Wed Mar 06 19:09:14 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!ttanaka From: ttanaka@stanford.edu (Takeshi Tanaka) Newsgroups: comp.sys.m68k Subject: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar06.190914.2728@stanford.edu> Date: Wed, 06 Mar 1996 19:09:14 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization! I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Takeshi Tanaka Hayes Optima 288 @ 9600 Telebit bps "We don't sign stars. We build them." From bsokolov@rwth-aachen.de Fri Mar 08 18:54:14 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!rwth-aachen!bsokolov From: bsokolov@rwth-aachen.de (Bastien Sokolov) Newsgroups: comp.sys.m68k Subject: Re: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar08.185414.2990@rwth-aachen.de> Date: Fri, 08 Mar 1996 18:54:14 GMT References: <1996Mar06.190914.2728@stanford.edu> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Mar06.190914.2728@stanford.edu>, ttanaka@stanford.edu (Takeshi Tanaka) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Bastien Sokolov | bsokolov@rwth-aachen.de PGP Key fingerprint: EBF6 66FB A636 F74F "Keep the channels open." From msuzuki@uni-hamburg.de Sun Mar 10 06:33:14 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uni-hamburg!msuzuki From: msuzuki@uni-hamburg.de (Mikhail Suzuki) Newsgroups: comp.sys.m68k Subject: Re: Discussion: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar10.063314.2898@uni-hamburg.de> Date: Sun, 10 Mar 1996 06:33:14 GMT References: <1996Mar06.190914.2728@stanford.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Mar06.190914.2728@stanford.edu>, ttanaka@stanford.edu (Takeshi Tanaka) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization! Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Mikhail Suzuki "Do not worship the copy." Atari Falcon 030 / TOS 4.04