Re: [Discuss-gnuradio] B200 clock calibration

[Robert Light]

> 2 kHz offset is within tolerance for 1900 MHz. Locking to a stable 10
> MHz reference, generally an OCXO or GPSDO, is the recommended
> approach.

I applied external 10MHz reference, the best I had at hand.
Now kalibrate says I have about 200Hz offset at 900MHz and 420Hz at 1800MHz, 
but  phones still do not want  to register to OpenBTS. A few phones that did 
not see the network before, are now seeing the network.  They see the network, 
but they say "no access" when I try to register. I configured OpenBTS to allow 
everything to register with no restrictions. The same computer was working with 
B100 a few weeks ago without any problems. I now have a few B200 but none of 
them works. They all behave the same way.

Is there a point in going for a more accurate clock ? I am already below 500Hz 
at 1900MHz. 
Did anyone get OpenBTS working on B200 ?
In the log I see regular "Sample buffer: Overrun". Can I do anything about it?
There is no sign in OpenBTS log that a phone is trying to register.


May 14 13:33:29 lenovo-Edge transceiver: ERR 139674597304064 13:33:29.0 
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:33:30 lenovo-Edge transceiver: ERR 139674597304064 13:33:30.9 
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:34:29 lenovo-Edge transceiver: ERR 139674597304064 13:34:29.0 
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun
May 14 13:35:29 lenovo-Edge transceiver: ERR 139674597304064 13:35:29.0 
UHDDevice.cpp:780:readSamples: Sample buffer: Overrun

May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
UHDDevice.cpp:737:readSamples: Requested timestamp = 792.358
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251049728 14:42:40.0 
Transceiver.cpp:774:driveTransmitFIFO: radio clock 5:1319506
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
Transceiver.cpp:358:pullRadioVector: looking for TSC at time: 1:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
Transceiver.cpp:358:pullRadioVector: looking for TSC at time: 2:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
Transceiver.cpp:358:pullRadioVector: looking for TSC at time: 3:1319505
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
UHDDevice.cpp:737:readSamples: Requested timestamp = 792.36
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251049728 14:42:40.0 
Transceiver.cpp:774:driveTransmitFIFO: radio clock 7:1319506
May 14 14:42:40  transceiver: last message repeated 2 times
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
UHDDevice.cpp:772:readSamples: Received timestamp = 792.357
May 14 14:42:40 lenovo-Edge transceiver: DEBUG 140528251016960 14:42:40.0 
Transceiver.cpp:358:pullRadioVector: looking for TSC at time: 4:1319505