From tkarlsson@unam.mx Sun Feb 27 05:05:42 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!unam!tkarlsson
From: tkarlsson@unam.mx (Takeshi Karlsson)
Newsgroups: comp.sys.m68k
Subject: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Feb27.050542.8289@unam.mx>
Date: Sun, 27 Feb 1994 05:05:42 GMT
Organization: Universidad Nacional Autónoma de México (DGSCA)
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Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier.

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

Does anyone want to test on an unaccelerated Amiga 500 with 512K chip RAM?

-- 
Takeshi Karlsson -- Universidad Nacional Autónoma de México (DGSCA)
"Row 14. No joke."

From aivanov@illinois.edu Sun Feb 27 08:36:42 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!aivanov
From: aivanov@illinois.edu (Amy Ivanov)
Newsgroups: comp.sys.m68k
Subject: Re: Question: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA
Message-ID: <1994Feb27.083642.3175@illinois.edu>
Date: Sun, 27 Feb 1994 08:36:42 GMT
References: <1994Feb27.050542.8289@unam.mx>
Organization: University of Illinois Urbana-Champaign
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In article <1994Feb27.050542.8289@unam.mx>, tkarlsson@unam.mx (Takeshi Karlsson) writes:
> Wrote an Amiga assembly program that uses Paula's DMA audio channels to sample and track the Stardust subcarrier.
> 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.

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

-- 
Amy Ivanov
Tape trading list upon request. SASE required for international mail.