From dlindqvist@cmu.edu Wed Mar 01 03:50:56 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!dlindqvist From: dlindqvist@cmu.edu (Diego Lindqvist) Newsgroups: comp.sys.m68k Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Mar01.035056.3161@cmu.edu> Date: Wed, 01 Mar 1995 03:50:56 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu 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. When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization! Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Diego Lindqvist "We don't sign stars. We build them." Acorn RiscPC 600 / Linux 1.2.13 From mmoreno@stanford.edu Wed Mar 01 07:04:56 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!stanford!mmoreno From: mmoreno@stanford.edu (Mike Moreno) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1995Mar01.070456.7342@stanford.edu> Date: Wed, 01 Mar 1995 07:04:56 GMT References: <1995Mar01.035056.3161@cmu.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 12 In article <1995Mar01.035056.3161@cmu.edu>, dlindqvist@cmu.edu (Diego Lindqvist) 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. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- === Mike Moreno === Dept of Electrical Engineering, Stanford University Computer Systems Lab "Do not worship the copy."