Questions about filter replacement and fbsb_req

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Pe oxccoxcc at yandex.ru
Wed Dec 12 13:55:58 UTC 2012


Hi list! 
I'm playing with ccch_scan from burst_ind branch.
I have some troubles with going SDCCH - FCCH\SCH - TCH
After receiving "assignment command" i call fbsb_req to L1 for waiting
FCCH\SCH sync bursts.
When fbsb_resp is coming, i call dm_est_req_h1 with channel and hopping
params. But SNR of incoming tch bursts is less then 10 most of time.   
What did i wrong?
Is it needs to synchronize only timers by SCH without FCCH freq sync? 
And why we lose sync when goes from SDCCH to TCH? 

And a question about filter replacement.
After filter change on baluns i see -128 dBm on all ARFCNs when mobile app
from master branch is started. After that i tried to connect balanced line
to the former filter pad and unbalanced line to the ground via cap(on the
EGSM channel), as Sylvain wrote. But it didnt help.

Photo after filter rework on C115:
http://s9.postimage.org/r50qtx73z/lastrep.jpg

As i understand, the input tract with 2 caps, 2 inductors and band-pass
filter just needs for image frequency disabling?



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