From jjohansson@uni-hamburg.de Tue Oct 08 20:58:59 1996 Path: ashpoly!cascade!transat!ukc!fennimore!uni-hamburg!jjohansson From: jjohansson@uni-hamburg.de (Jen Johansson) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct08.205859.9194@uni-hamburg.de> Date: Tue, 08 Oct 1996 20:58:59 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de 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. 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. I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Jen Johansson *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From kpetrov@cern.ch Wed Oct 09 00:31:59 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!cern!kpetrov From: kpetrov@cern.ch (Kirsty Petrov) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct09.003159.8073@cern.ch> Date: Wed, 09 Oct 1996 00:31:59 GMT References: <1996Oct08.205859.9194@uni-hamburg.de> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Oct08.205859.9194@uni-hamburg.de>, jjohansson@uni-hamburg.de (Jen Johansson) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Kirsty Petrov | kpetrov@cern.ch PGP Key fingerprint: 3EEB A1B4 B911 DE4A "Keep the channels open." From eeriksson@stanford.edu Thu Oct 10 14:18:59 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!eeriksson From: eeriksson@stanford.edu (Elaine Eriksson) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct10.141859.9803@stanford.edu> Date: Thu, 10 Oct 1996 14:18:59 GMT References: <1996Oct08.205859.9194@uni-hamburg.de> <1996Oct09.003159.8073@cern.ch> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Oct09.003159.8073@cern.ch>, kpetrov@cern.ch (Kirsty Petrov) writes: > Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Elaine Eriksson *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From tvasiliev@illinois.edu Fri Oct 11 20:53:59 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!tvasiliev From: tvasiliev@illinois.edu (Takeshi Vasiliev) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct11.205359.1699@illinois.edu> Date: Fri, 11 Oct 1996 20:53:59 GMT References: <1996Oct08.205859.9194@uni-hamburg.de> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Oct08.205859.9194@uni-hamburg.de>, jjohansson@uni-hamburg.de (Jen Johansson) 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. -- Takeshi Vasiliev "Hold for relay." Sun 3/60 (SunOS 4.1.1) / FreeBSD 2.1 From spopov@kth.se Fri Oct 11 23:57:59 1996 Path: ashpoly!cascade!bigsur!kth!spopov From: spopov@kth.se (Sun-mi Popov) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Oct11.235759.8834@kth.se> Date: Fri, 11 Oct 1996 23:57:59 GMT References: <1996Oct08.205859.9194@uni-hamburg.de> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1996Oct08.205859.9194@uni-hamburg.de>, jjohansson@uni-hamburg.de (Jen Johansson) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > 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. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. If you are posting from AOL, please read RFC 1036 before posting again. -- Sun-mi Popov | spopov@kth.se PGP Key fingerprint: E573 4BB4 F740 7ABE "Keep the channels open."