From rgarcia@stanford.edu Fri Aug 18 11:07:51 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!stanford!rgarcia From: rgarcia@stanford.edu (Renata García) Newsgroups: comp.sys.m68k Subject: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug18.110751.3001@stanford.edu> Date: Fri, 18 Aug 1995 11:07:51 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 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. Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM? -- Renata García *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From tbrennan@berkeley.edu Sun Aug 20 15:06:51 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!berkeley!tbrennan From: tbrennan@berkeley.edu (Thiago Brennan) Newsgroups: comp.sys.m68k Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug20.150651.7151@berkeley.edu> Date: Sun, 20 Aug 1995 15:06:51 GMT References: <1995Aug18.110751.3001@stanford.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Aug18.110751.3001@stanford.edu>, rgarcia@stanford.edu (Renata García) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. -- Thiago Brennan "We don't sign stars. We build them." Amiga 3000T / AmigaOS 3.1 From awatanabe@berkeley.edu Mon Aug 21 03:17:51 1995 Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!awatanabe From: awatanabe@berkeley.edu (Astrid Watanabe) Newsgroups: comp.sys.m68k Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Aug21.031751.5016@berkeley.edu> Date: Mon, 21 Aug 1995 03:17:51 GMT References: <1995Aug18.110751.3001@stanford.edu> <1995Aug20.150651.7151@berkeley.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Aug20.150651.7151@berkeley.edu>, tbrennan@berkeley.edu (Thiago Brennan) writes: > Tested on my A3000 / 25 MHz. Ran smoothly in the background while I was compiling a C program in another window. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. -- Astrid Watanabe *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0