From itakahashi@kth.se Sat Mar 12 23:16:27 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!kth!itakahashi From: itakahashi@kth.se (Ines Takahashi) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Mar12.231627.4779@kth.se> Date: Sat, 12 Mar 1994 23:16:27 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se 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. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Ines Takahashi | itakahashi@kth.se PGP Key fingerprint: 3F88 E5F6 412A 0503 "Keep the channels open." From civanov@uni-hamburg.de Mon Mar 14 18:40:27 1994 Path: ashpoly!cascade!transat!ukc!fennimore!uni-hamburg!civanov From: civanov@uni-hamburg.de (Camila Ivanov) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Mar14.184027.5872@uni-hamburg.de> Date: Mon, 14 Mar 1994 18:40:27 GMT References: <1994Mar12.231627.4779@kth.se> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Mar12.231627.4779@kth.se>, itakahashi@kth.se (Ines Takahashi) writes: > 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Camila Ivanov | civanov@uni-hamburg.de PGP Key fingerprint: 614F CEF3 7EB2 6FE6 "Keep the channels open." From eeriksson@uu.net Mon Mar 14 22:46:27 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!uu!eeriksson From: eeriksson@uu.net (Elaine Eriksson) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Mar14.224627.8099@uu.net> Date: Mon, 14 Mar 1994 22:46:27 GMT References: <1994Mar12.231627.4779@kth.se> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Mar12.231627.4779@kth.se>, itakahashi@kth.se (Ines Takahashi) writes: > 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. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Elaine Eriksson "A soul is not exclusive to biology." Sun 3/60 (SunOS 4.1.1) / TOS 4.04 From ssmirnov@inria.fr Wed Mar 16 16:34:27 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!inria!ssmirnov From: ssmirnov@inria.fr (Steve Smirnov) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Mar16.163427.4273@inria.fr> Date: Wed, 16 Mar 1994 16:34:27 GMT References: <1994Mar12.231627.4779@kth.se> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Mar12.231627.4779@kth.se>, itakahashi@kth.se (Ines Takahashi) 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. -- Steve Smirnov SupraFAXModem 28.8 @ 19,200 bps "Measuring a record you own is listening, not piracy."