From mgonzalez@cam.ac.uk Mon Apr 01 14:09:52 1996 Path: ashpoly!cascade!brgate!saturno!cam!mgonzalez From: mgonzalez@cam.ac.uk (Morag González) Newsgroups: comp.sys.m68k Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr01.140952.9770@cam.ac.uk> Date: Mon, 01 Apr 1996 14:09:52 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk 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. 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. Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- === Morag González === Dept of Electrical Engineering, University of Cambridge Computer Laboratory "Marcus is not one man." From kito@delphi.com Tue Apr 02 06:40:52 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!delphi!kito From: kito@delphi.com (Kenji Ito) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr02.064052.7966@delphi.com> Date: Tue, 02 Apr 1996 06:40:52 GMT References: <1996Apr01.140952.9770@cam.ac.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Apr01.140952.9770@cam.ac.uk>, mgonzalez@cam.ac.uk (Morag González) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image? Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Kenji Ito "Row 14. No joke." Amiga 3000T / Linux 1.2.13 From dhughes@netcom.com Tue Apr 02 17:48:52 1996 Path: ashpoly!cascade!transat!ukc!fennimore!netcom!dhughes From: dhughes@netcom.com (Diego Hughes) Newsgroups: comp.sys.m68k Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Apr02.174852.4289@netcom.com> Date: Tue, 02 Apr 1996 17:48:52 GMT References: <1996Apr01.140952.9770@cam.ac.uk> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Apr01.140952.9770@cam.ac.uk>, mgonzalez@cam.ac.uk (Morag González) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Download failed on Aminet mirror. Can someone mail me an ADF floppy disk image? -- Diego Hughes Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services. ------------------------------------------------------------