From sito@kth.se Sat May 11 03:10:51 1996 Path: ashpoly!cascade!bigsur!kth!sito From: sito@kth.se (Sven Ito) Newsgroups: comp.sys.m68k Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996May11.031051.5705@kth.se> Date: Sat, 11 May 1996 03:10:51 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se 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. Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week. -- Sven Ito | sito@kth.se PGP Key fingerprint: 9C84 E6FA F160 D2E6 "Keep the channels open." From bkowalski@clari.net Sun May 12 22:05:51 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!clari!bkowalski From: bkowalski@clari.net (Bastien Kowalski) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996May12.220551.9792@clari.net> Date: Sun, 12 May 1996 22:05:51 GMT References: <1996May11.031051.5705@kth.se> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1996May11.031051.5705@kth.se>, sito@kth.se (Sven Ito) 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Bastien Kowalski -- ClariNet Communications Corp "We don't sign stars. We build them." From mduarte@uu.net Mon May 13 18:24:51 1996 Path: ashpoly!cascade!transat!ukc!fennimore!uu!mduarte From: mduarte@uu.net (Min-jun Duarte) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996May13.182451.7861@uu.net> Date: Mon, 13 May 1996 18:24:51 GMT References: <1996May11.031051.5705@kth.se> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996May11.031051.5705@kth.se>, sito@kth.se (Sven Ito) 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. Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. -- Min-jun Duarte Tape trading list upon request. SASE required for international mail. From skarlsson@kiae.su Wed May 15 15:59:51 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!kiae!skarlsson From: skarlsson@kiae.su (Seo-yeon Karlsson) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996May15.155951.8462@kiae.su> Date: Wed, 15 May 1996 15:59:51 GMT References: <1996May11.031051.5705@kth.se> <1996May13.182451.7861@uu.net> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 9 In article <1996May13.182451.7861@uu.net>, mduarte@uu.net (Min-jun Duarte) writes: > Please make sure it's compatible with Kickstart 1.3 for those of us who haven't upgraded our A500s to 3.1 yet. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Seo-yeon Karlsson "Marcus is not one man." Acorn RiscPC 600 / NEXTSTEP 3.3