Well. It is Tx carrier frequency, which is typically below the modulated signal on 40..60 dB. You can see it on spectrum analyzer when there are no modulation.
Best regards, Andrey Sviyazov. 2013/6/7 jiangwy <[email protected]> > ** > Hi Andrey. > > I see. But what's the TxLO leakage? > > ------------------------------ > jiangwy > > *From:* Andrey Sviyazov <[email protected]> > *Date:* 2013-06-07 19:14 > *To:* wyjiang <[email protected]> > *CC:* umtrx <[email protected]>; Chemeris > Alexander<[email protected]> > *Subject:* Re: Re: Time to Switching Frequence > > Hi Jiang. > > Sorry, I missed that you'll use only receivers. > So, no any problems in this case. > > Best regards, > Andrey Sviyazov. > (Sent from my mobile client) > 07.06.2013 14:54 пользователь "Andrey Sviyazov" <[email protected]> > написал: > >> Hi Jiang. >> >> Please remember that Rx and Tx of LMS can't work well at the same >> frequency due to PLL's problems. >> Also, please do not forget about TxLO leakage which is quite significant. >> >> Best regards, >> Andrey Sviyazov. >> (Sent from my mobile client) >> 07.06.2013 14:36 пользователь "jiangwy" <[email protected]> написал: >> >>> ** >>> OK. >>> Thank you and Sylvain very much! >>> >>> ------------------------------ >>> jiangwy >>> >>> *From:* Alexander Chemeris <[email protected]> >>> *Date:* 2013-06-07 18:12 >>> *To:* wyjiang <[email protected]> >>> *CC:* UmTRX <[email protected]> >>> *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 <[email protected]> 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 >>> >>
