From dhughes@earthlink.net Tue Mar 05 23:02:40 1996 Path: ashpoly!cascade!bigsur!earthlink!dhughes From: dhughes@earthlink.net (Diego Hughes) Newsgroups: comp.sys.m68k Subject: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar05.230240.8312@earthlink.net> Date: Tue, 05 Mar 1996 23:02:40 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 10 Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Diego Hughes -- EarthLink Network "In theory there is no difference between theory and practice." From dgonzalez@delphi.com Wed Mar 06 19:34:40 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!delphi!dgonzalez From: dgonzalez@delphi.com (Dong-hyun González) Newsgroups: comp.sys.m68k Subject: Re: WTB/WTT: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1996Mar06.193440.9285@delphi.com> Date: Wed, 06 Mar 1996 19:34:40 GMT References: <1996Mar05.230240.8312@earthlink.net> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1996Mar05.230240.8312@earthlink.net>, dhughes@earthlink.net (Diego Hughes) writes: > Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier. > I wrote a 64-tap FIR filter in pure 68k assembly using movem.l and dbra loop unrolling to downsample to 64 Hz. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! If you are posting from AOL, please read RFC 1036 before posting again. -- Dong-hyun González *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0