J.Bastemeijer at TUDelft.nl
Mon Jun 4 06:01:35 EDT 2007
I'm working at Delft University. I know the group were Durk van Willigen
used to work. He is now director of a company producing LORAN-related
(timing) products (Reelektronika.nl).
A technician who used to work for him is still around in the university.
I talked to him lately, but most of the knowledge about the LORAN
reception has faded away... Allthough, if there are specific questions I
might convince him to dig a little bit deeper in his memory ;-)
Greetings and 73's Jeroen PE1RGE
Enrico Rubiola wrote:
>the old good Loean-C is still alive, as I can see.
>There is a funny thing about the receiver. The case
>of loran signal is that of finding the zero-crossings in
>a very polluted signal.
>The receivers designed in the '80s use a 1bit ADC
>(hard limiter) sampling at some 10 MHz, and find the
>zero crossings through the statistics of 0s and 1s at the
>converter output. They identify the envelope (needed
>for the zero crossing at 30 microsec from the origin of
> the envelope) in this way.
>It has been demonstrated that in the case of detecting the
>zero crossings in highly polluted signals, if the hard limiter
>is used instead of the full resolution of an ideal ADC (infinite
>number of bits), the SNR is made worse by less than 2 dB.
>There are a few articles written by Durke van Viilligen,
>Delft University, somewhere between 1975 and 1980.
>On request, I can dig deeper in my memory and hard disks.
>professor of electronics
>e-mail: rubiola at femto-st.fr
>32 av. de l'Observatoire
>25044 Besancon, FRANCE
>voice: +33(0)381.853940 (E.Rubiola)
>voice: +33(0)381.853999 (switchboard)
>time-nuts mailing list
>time-nuts at febo.com
Ing. Jeroen Bastemeijer
Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
E-mail: J.Bastemeijer at TUDelft.nl
GPS: Lat N52.00002 Lon E4.37157 Alt 46.2m
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