22 Jul
2009
22 Jul
'09
12:28 p.m.
Hi!
So for everyone who has problems with BS-11 clock accuracy,
what would be the theoretical straight-forward way to solve the
problem, is to replace the 32.768MHz crystal oscillator on the E1
card with a OCXO of the same frequency.
So what we're looking for is an OCXO with +/- 0.05ppm or higher stability for
3.3V power supply. Unfortunately I was not able to find one at that
frequency, even digikey doesn't have one.
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.
Thanks!
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
23 Jul
23 Jul
10:36 a.m.
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/
6:09 p.m.
On Thu, Jul 23, 2009 at 10:36:44AM +0200, Michael Gernoth wrote:
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.
Ok, thanks. It seems I'll have to do the same thing and pre-calibrate
the BS-11 units that we'll be taking to HAR2009, as we certainly won't
have any actual ISDN lines there...
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
24 Jul
24 Jul
1:10 p.m.
Hi,
On Thu, Jul 23, 2009 at 06:09:57PM +0200, Harald Welte wrote:
Ok, thanks. It seems I'll have to do the same
thing and pre-calibrate
the BS-11 units that we'll be taking to HAR2009, as we certainly won't
have any actual ISDN lines there...
One pre-calibrated unit should be enough, as you should be able to use the
clock generated by one BS-11 as PCM master clock for another HFC card
with a second unit attached.
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/
8:09 p.m.
On Fri, Jul 24, 2009 at 01:10:26PM +0200, Michael Gernoth wrote:
Hi,
On Thu, Jul 23, 2009 at 06:09:57PM +0200, Harald Welte wrote:
I'm planning to use only one E1 card. Yes, theoretically that should still
work with only one calibrated unit, but I'd rather not take my chances.
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
Ok, thanks. It seems I'll have to do the
same thing and pre-calibrate
the BS-11 units that we'll be taking to HAR2009, as we certainly won't
have any actual ISDN lines there...
One pre-calibrated unit should be enough, as you should be able to use the
clock generated by one BS-11 as PCM master clock for another HFC card
with a second unit attached.
5397
days inactive
5399
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4 comments
2 participants
participants (2)
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Harald Welte -
Michael Gernoth