Re: [Discuss-gnuradio] B200 clock calibration

[Martin Braun]

On 14.05.2014 12:12, Robert Light wrote:
> I try to get B200 to work with OpenBTS and I see some frequency offset in the 
> internal reference clock.
> Does anyone know if the numbers I get from kalibrate, could cause phones not to 
> be able to register to OpenBTS?
>   What is the quickest and the cheapest way fix a problem with a clock? I
> think B200 has TCVCXO, so is there a way to write some tuning voltage offset to
>   correct the frequency? Do a clock calibration?  Does anyone know the exact 
> part nr of TCVCXO
>   mounted in B200?
>
>   UHD Warning:
>   The hardware does not support the requested RX sample rate:
>   Target sample rate: 0.270833 MSps
>   Actual sample rate: 0.271186 MSps

Robert,

as long as you see this warning, you'll get offsets. I don't know where 
or how kal sets up the master clock, but you should put in a 
master_clock_rate=13e6 somewhere in there.

M

>   kal: Scanning for GSM-900 base stations.
>   chan: 19 (938.8MHz + 1.915kHz) power: 2812.45
>   chan: 26 (940.2MHz + 1.900kHz) power: 14595.33
>   chan: 33 (941.6MHz + 1.913kHz) power: 18358.13
>   chan: 58 (946.6MHz + 1.930kHz) power: 9563.79
>   chan: 114 (957.8MHz + 1.957kHz) power: 1872.65
>
>   Using GSM-900 channel 19 (938.8MHz)
>   average [min, max] (range, stddev)
>   + 1.896kHz [1855, 1943] (88, 19.746572)
>   overruns: 0
>   not found: 92
>
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