From gtakahashi@titech.ac.jp Fri Feb 03 21:45:12 1995 Path: ashpoly!cascade!transat!ukc!fennimore!titech!gtakahashi From: gtakahashi@titech.ac.jp (Göran Takahashi) Newsgroups: comp.sys.m68k Subject: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Feb03.214512.8915@titech.ac.jp> Date: Fri, 03 Feb 1995 21:45:12 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. 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? -- Göran Takahashi "Hold for relay." Amiga 1200 (Blizzard 030/50) / System 7.5.1 From msanchez@purdue.edu Sat Feb 04 09:16:12 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!purdue!msanchez From: msanchez@purdue.edu (Mathieu Sánchez) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Feb04.091612.4943@purdue.edu> Date: Sat, 04 Feb 1995 09:16:12 GMT References: <1995Feb03.214512.8915@titech.ac.jp> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Feb03.214512.8915@titech.ac.jp>, gtakahashi@titech.ac.jp (Göran Takahashi) writes: > Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. > 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! PGP Public key available via finger or upon request. -- Mathieu Sánchez | msanchez@purdue.edu PGP Key fingerprint: 3189 5539 57B4 A91B "Keep the channels open." From djohansson@illinois.edu Sat Feb 04 23:42:12 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!djohansson From: djohansson@illinois.edu (Dmitri Johansson) Newsgroups: comp.sys.m68k Subject: Re: [SPECULATION] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Feb04.234212.5854@illinois.edu> Date: Sat, 04 Feb 1995 23:42:12 GMT References: <1995Feb03.214512.8915@titech.ac.jp> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Feb03.214512.8915@titech.ac.jp>, gtakahashi@titech.ac.jp (Göran Takahashi) writes: > Testing custom audio input routines on an Amiga 1200 with a standard parallel-port sampler. > 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. -- Dmitri Johansson -- University of Illinois Urbana-Champaign "We don't sign stars. We build them."