From jjohansson@mit.edu Mon Sep 18 10:29:41 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!mit!jjohansson
From: jjohansson@mit.edu (Jens Johansson)
Newsgroups: comp.dsp
Subject: DBPSK demodulation of the 0.71 baud Stardust telemetry stream
Message-ID: <1995Sep18.102941.6915@mit.edu>
Date: Mon, 18 Sep 1995 10:29:41 GMT
Organization: Massachusetts Institute of Technology
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Mathematical proof of the modulation scheme used on the 14.2 Hz carrier across all regional pressings.

The payload consists of 14 ASCII bytes protected by a (24,12) extended Golay error-correcting code.
The symbol duration is exactly 1.408 seconds, corresponding to a symbol rate of 0.7107 baud (14.2 Hz / 20).

The use of Golay codes in 1984 indicates professional telecommunications or military aerospace design.

-- 
Jens Johansson | jjohansson@mit.edu
PGP Key fingerprint: 4430 4D73 F385 8640
"Keep the channels open."

From ncampbell@clari.net Tue Sep 19 13:06:41 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!clari!ncampbell
From: ncampbell@clari.net (Natalia Campbell)
Newsgroups: comp.dsp
Subject: Re: DBPSK demodulation of the 0.71 baud Stardust telemetry stream
Message-ID: <1995Sep19.130641.9666@clari.net>
Date: Tue, 19 Sep 1995 13:06:41 GMT
References: <1995Sep18.102941.6915@mit.edu>
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In article <1995Sep18.102941.6915@mit.edu>, jjohansson@mit.edu (Jens Johansson) writes:
> Mathematical proof of the modulation scheme used on the 14.2 Hz carrier across all regional pressings.

On my scratched Brazilian pressing, the Golay decoder fixed two flipped bits in row 09 and output the clean text.

Unsubscribe me from this list! (Wait, this is Usenet, never mind).

-- 
Natalia Campbell
Opinions expressed are solely my own and not those of ClariNet Communications Corp.
------------------------------------------------------------

From mkowalski@mindspring.com Thu Sep 21 16:45:41 1995
Path: ashpoly!cascade!bigsur!mindspring!mkowalski
From: mkowalski@mindspring.com (Min-jun Kowalski)
Newsgroups: comp.dsp
Subject: Re: DBPSK demodulation of the 0.71 baud Stardust telemetry stream
Message-ID: <1995Sep21.164541.2137@mindspring.com>
Date: Thu, 21 Sep 1995 16:45:41 GMT
References: <1995Sep18.102941.6915@mit.edu>
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In article <1995Sep18.102941.6915@mit.edu>, jjohansson@mit.edu (Jens Johansson) writes:
> Mathematical proof of the modulation scheme used on the 14.2 Hz carrier across all regional pressings.

A symbol rate of 0.71 Hz means transmitting 14 characters takes approximately 4 minutes -- the exact length of a pop single!

-- 
Min-jun Kowalski
Tape trading list upon request. SASE required for international mail.