UmTRX

Alexander Chemeris alexander.chemeris at gmail.com
Mon Jun 17 11:53:20 UTC 2013


Albert,

In this case yes, it's possible. You could get RXOUT values on
the four test points at the north-west corner of the chip (TST5 - TST8).
Note, that they are differential and separate I/Q.

To acquire 25MHZ you could set LPF to 28MHz, as Sylvain pointed or
completely disable it. I strongly recommend you to use an external bandpass
filter in the latter case.

On Mon, Jun 17, 2013 at 2:08 PM, Albert-Miquel Sánchez <albertm at salleurl.edu
> wrote:

> Thank you very much for your response. I didn’t mention it, but I only
> want to extract the analog signal (the 25 MHz baseband bandwidth), in order
> to analyze the spectral content (I would capture this signal with another
> board developed by us). Therefore, I don’t need to process it with the
> UmTRX. However I need the UmTRX in order to do this analysis while keeping
> a phone communication.****
>
> ** **
>
> Best regards,****
>
> ** **
>
> Albert****
>
> ** **
>
> *De:* john.wilson at pathintel.com [mailto:john.wilson at pathintel.com] *En
> nombre de *John Wilson
> *Enviado el:* lunes, 17 de junio de 2013 11:41
> *Para:* Albert-Miquel Sánchez
> *CC:* umtrx at lists.osmocom.org
> *Asunto:* Re: UmTRX****
>
> ** **
>
> If you need to extract them all simultaneously then you'd need about 25
> MHz baseband bandwidth, which I think at the moment is a bit more than the
> UmTRX can do on one channel, you might be able to do something clever and
> look across both channels maybe. That's a whole lot of processing as well,
> I'm guessing you'll be analyzing the signals offline? USRP2 or USRP N
> series and do about 25 MHz sustained on one channel, you'll need some good
> network hardware on your PC to prevent overruns.****
>
> John****
>
> ** **
>
> On 17 June 2013 10:23, Albert-Miquel Sánchez <albertm at salleurl.edu> wrote:
> ****
>
> Hello,****
>
> I’m an engineer from Spain and I’m interested in a GSM receiver because I
> would like to study the internal signals for a research project. In
> particular, I’m interested in the analysis of the IF signal, but, as
> Alexander told me, the LMS6002D uses zero-IF architecture, so there is no
> real "IF" signal, there is only baseband signal. I guess I could also use
> this signal for my purposes, but only if all 124 GSM channels can be found
> at that point. I’m not sure if this is possible, since there is a low-pass
> filter before. Does anybody know if I can extract that information, that
> is, the analogic 124 channels after the RF mixer? If it is not possible
> with this board, does anybody know if I can do it with another GSM
> transceiver board?****
>
> Thank you very much in advance.****
>
> Best regards,****
>
> Albert****
>
>
>
>
> --
> *Dr. John Wilson*
> Product development engineer, Path Intelligence<http://www.pathintelligence.com/>
> T +44 2392 388442    @pathintel
> DETECT • ANALYSE • PREDICT • INFLUENCE
>
>
> Path Intelligence Limited, registered number 5176274. Registered in
> England,
> registered office at 1000 Lakeside North Harbour, Western Road,
> Portsmouth, UK, PO6 3EN ****
>



-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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