Looking for 32.768MHz OCXO for BS-11 calibration

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Michael Gernoth Michael.Gernoth at informatik.uni-erlangen.de
Thu Jul 23 08:36:44 UTC 2009


Hi,

On Wed, Jul 22, 2009 at 12:28:55PM +0200, Harald Welte wrote:
> If anyone can find a source for a OCXO in the abovementioned
> parameter range (and small quantities), I think quite a number of people would
> be interested in buying one and connecting it to their E1 boards.  Any help
> is much appreciated.

After having given up on the same task, I decided to try Andreas'
isdnsync using my ISDN line. I synchronized the clock of the BS-11
by connecting it to a cheap HFC-S PCI card and connecting that to
the ISDN network.

I just connected C4IO and F0IO, added type=0x00800 to the hfcmulti
parameters, ran isdnsync and started bsc_hack. I could then watch the
oscillator frequency getting slowly adjusted to the ISDN line with
bs11_config (the value changed from somewhere around 1840 to 1035).
It took about an hour for the work value to stablilize.

Now all available mobiles can see and join the network and are also able
to find and join the official networks again.

I've uploaded a (bad) picture of the modified card here:
http://www4.cs.fau.de/~gernoth/IMG_8005.JPG
The attached cable can be directly plugged in to one of
the PCM connectors on the E1 board (PIN 9 and 11).

Regards,
  Michael

-- 
Michael Gernoth                            Department of Computer Science IV 
Martensstrasse 1  D-91058 Erlangen Germany  University of Erlangen-Nuremberg
	      http://www4.informatik.uni-erlangen.de/~gernoth/




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