Time to Switching Frequence

jiangwy wyjiang at ljshuoda.com
Fri Jun 7 10:33:31 UTC 2013


OK.
Thank you and Sylvain very much!




jiangwy

From: Alexander Chemeris
Date: 2013-06-07 18:12
To: wyjiang
CC: UmTRX
Subject: Re: Time to Switching Frequence
Jiang,

It's not tested. LMS6002D chip by itself has quite short tuning time,
but the current host and FPGA code introduce significant delay. I
can't find exact numbers regarding LMS tuning time, but IIRC it was
shorter than a GSM timeslot.

So, as Sylvain said, given software limitations it's easier to use two
channels of UmTRX to receive on two frequencies.

On Fri, Jun 7, 2013 at 11:21 AM, jiangwy <wyjiang at ljshuoda.com> wrote:
> Hi All,
>
> I have a project to monitoring ( air sniffer ) the data between GSM BTS and
> MS using UmTRX.
> Uplink Transmission is delayed 3 slots than downlink from specification.
> So when I sync. with BTS and get the downlink slot data, I must switch the
> freqs of receiver from downlink to uplink in less than 2 slots.
> When the program call 'usrp_dev->set_rx_freq(wFreq)', How much time does the
> UmTRX switch to the 'wFreq' ?
>
> Thanks in advance.
>
> ________________________________
> Jiang WenYi



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