From kkowalski@mindspring.com Thu Apr 04 08:53:41 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!mindspring!kkowalski From: kkowalski@mindspring.com (Katrin Kowalski) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr04.085341.3132@mindspring.com> Date: Thu, 04 Apr 1996 08:53:41 GMT Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com 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. -- Katrin Kowalski Zyxel U-1496E @ 19,200 bps "Hold for relay." From ohughes@delphi.com Thu Apr 04 14:27:41 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!delphi!ohughes From: ohughes@delphi.com (Olga Hughes) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr04.142741.4644@delphi.com> Date: Thu, 04 Apr 1996 14:27:41 GMT References: <1996Apr04.085341.3132@mindspring.com> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Apr04.085341.3132@mindspring.com>, kkowalski@mindspring.com (Katrin Kowalski) 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. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Olga Hughes "Extraordinary claims require extraordinary spectra." NeXTstation Turbo Color / AmigaOS 3.1 From agonzalez@cern.ch Fri Apr 05 02:20:41 1996 Path: ashpoly!cascade!bigsur!cern!agonzalez From: agonzalez@cern.ch (Anja González) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr05.022041.7570@cern.ch> Date: Fri, 05 Apr 1996 02:20:41 GMT References: <1996Apr04.085341.3132@mindspring.com> <1996Apr04.142741.4644@delphi.com> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Apr04.142741.4644@delphi.com>, ohughes@delphi.com (Olga Hughes) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Anja González "The carrier frequency does not drift by accident." Amiga 1200 (Blizzard 030/50) / System 7.5.1 From ereyes@mit.edu Fri Apr 05 16:57:41 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!mit!ereyes From: ereyes@mit.edu (Elaine Reyes) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr05.165741.6579@mit.edu> Date: Fri, 05 Apr 1996 16:57:41 GMT References: <1996Apr04.085341.3132@mindspring.com> <1996Apr04.142741.4644@delphi.com> <1996Apr05.022041.7570@cern.ch> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Apr05.022041.7570@cern.ch>, agonzalez@cern.ch (Anja González) writes: > Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! -- Elaine Reyes "Hardware is temporary. The signal survives." 486DX4/100 (FreeBSD 2.0.5) / SunOS 4.1.4