From akarlsson@mit.edu Sun Jan 01 16:33:00 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!mit!akarlsson From: akarlsson@mit.edu (Amy Karlsson) Newsgroups: comp.sys.m68k Subject: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan01.163300.7857@mit.edu> Date: Sun, 01 Jan 1995 16:33:00 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 10 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. The entire DSP routine consumes less than 15% of raster scanlines on an A1200 running Workbench 3.1. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Amy Karlsson -- Massachusetts Institute of Technology "Measuring a record you own is listening, not piracy." From mokonkwo@cmu.edu Sun Jan 01 22:02:00 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!mokonkwo From: mokonkwo@cmu.edu (Mike Okonkwo) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan01.220200.7562@cmu.edu> Date: Sun, 01 Jan 1995 22:02:00 GMT References: <1995Jan01.163300.7857@mit.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jan01.163300.7857@mit.edu>, akarlsson@mit.edu (Amy Karlsson) 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Mike Okonkwo Practical Peripherals 14.4 @ 9600 Telebit bps "There are 14 nodes and only 10 countries. Count again." From jmartinez@titech.ac.jp Tue Jan 03 01:44:00 1995 Path: ashpoly!cascade!transat!ukc!fennimore!titech!jmartinez From: jmartinez@titech.ac.jp (Jen Martínez) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan03.014400.6004@titech.ac.jp> Date: Tue, 03 Jan 1995 01:44:00 GMT References: <1995Jan01.163300.7857@mit.edu> <1995Jan01.220200.7562@cmu.edu> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Jan01.220200.7562@cmu.edu>, mokonkwo@cmu.edu (Mike Okonkwo) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! 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. -- Jen Martínez Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre. ------------------------------------------------------------ From meriksson@cern.ch Wed Jan 04 16:35:00 1995 Path: ashpoly!cascade!mxgate!coyoacan!cern!meriksson From: meriksson@cern.ch (Mike Eriksson) Newsgroups: comp.sys.m68k Subject: Re: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Jan04.163500.8364@cern.ch> Date: Wed, 04 Jan 1995 16:35:00 GMT References: <1995Jan01.163300.7857@mit.edu> <1995Jan01.220200.7562@cmu.edu> <1995Jan03.014400.6004@titech.ac.jp> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jan03.014400.6004@titech.ac.jp>, jmartinez@titech.ac.jp (Jen Martínez) writes: > 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. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Mike Eriksson | meriksson@cern.ch PGP Key fingerprint: 8EE4 C8F9 ACB1 74B7 "Keep the channels open."