Re: [Openbts-discuss] 52MHz clocking

[Alexander C. <ale...@gm...>]

Hi All,

So far we've got usrp_fft.py working and OpenBTS working to the
state we saw it before reclocking - i.e. phone can see the network,
but can't connect to it. I'm attaching the patches we have for this.

Now I'm looking at resampler to understand how should I modify it.

At this point when I start OpenBTS it bursts a lot of output to a screen
and then suddenly stops and I see only "uptime" messages being
pronted. Is that normal behaviour? I'm attaching OpenBTS stdout
outputto too.

On Wed, Sep 16, 2009 at 16:37, Alexander Chemeris
<ale...@gm...> wrote:
> Hi all,
>
> We've received our configurable clock generator and trying to get USRP
> working with it. It can't reliably work at 64MHz, but is stable enough at
> 52MHz. So we wonder how to switch OpenBTS to 52MHz clocking?
>
> We're using gnuradio-3.1.3 with OpenBTS-1.6. We've changed
> fpga_master_clock_freq() to return 52M instead of 64M and recompiled
> it. But when we run usrp_fft.py to check whether it tunes to correct frequency,
> we see that spectrum is off by about 64/52 (i.e. GSM is about 1.2GHz instead
> of 900Mz). What else should we change to make it working? Should
> I switch to newer gnuradio?
>
> Then, I looked at transceiver to see how to modify its resampler to work with
> 52MHz. But here I see that USRP freq (OUTRATE) is set to 96. Why is it
> not 64 and what should I set for 52MHz clock then?
>
> --
> Regards,
> Alexander Chemeris.
>



-- 
Regards,
Alexander Chemeris.