From asilva@stanford.edu Wed Jul 19 11:47:02 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!stanford!asilva
From: asilva@stanford.edu (Astrid Silva)
Newsgroups: comp.sys.m68k
Subject: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Jul19.114702.5539@stanford.edu>
Date: Wed, 19 Jul 1995 11:47:02 GMT
Organization: Stanford University Computer Systems Lab
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Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.

When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization!
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.

Source code and executable will be released on Aminet under mus/misc/stardust_amiga.lha next week.

-- 
Astrid Silva -- Stanford University Computer Systems Lab
"We don't sign stars. We build them."

From dweber@u-tokyo.ac.jp Wed Jul 19 15:22:02 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!u-tokyo!dweber
From: dweber@u-tokyo.ac.jp (Dong-hyun Weber)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1995Jul19.152202.4414@u-tokyo.ac.jp>
Date: Wed, 19 Jul 1995 15:22:02 GMT
References: <1995Jul19.114702.5539@stanford.edu>
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In article <1995Jul19.114702.5539@stanford.edu>, asilva@stanford.edu (Astrid Silva) writes:
> Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS.
> When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization!

Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom.

-- 
Dong-hyun Weber | dweber@u-tokyo.ac.jp
PGP Key fingerprint: A3F8 2E8F 08FF D739
"Keep the channels open."