Hi all, I have made an I/Q recording with a NI-USRP 2920, which includes a WBX daughterboard (input signal is a CW) When I do a playback of my recording at Fc=1GHz, and gain at minimum (0dB), I see the CW at -50dBm. I have switched the daughterboard of the USRP for a SBX. When I do the playback of the same recording at Fc=1GHz, and gain at minimum (0dB), I see the CW, but now at -40dBm. Q: Is it normal that the SBX daughterboard generates signals 10dB higher than the WBX daughterboard, when both are set to use the same gain? Or is there a parameter in UHD that should be set differently for the SBX daughterboard? I'm using an old version of UHD: 3.4.4 Thanks! Serge Serge Malo, ing. Développeur logiciel Principal Senior Software engineer sema@averna.com<mailto:sema@averna.com> T 514-842-7577x648 [http://www.averna.com/ec/signature/icons_2013/averna_linkedin_icon.gif]<http://www.linkedin.com/company/23210> [http://www.averna.com/ec/signature/icons_2013/averna_youtube_icon.gif]<http://www.youtube.com/user/avernamarketing> [http://www.averna.com/ec/signature/icons_2013/averna_twitter_icon.gif]<https://twitter.com/avernatech> [Averna - Test Engineering Expertise and Solutions]<http://www.averna.com/> PERSONNEL ET CONFIDENTIEL. Ce courriel et tout fichier joint contiennent de l'information confidentielle destinée au seul usage du destinataire ou de son représentant autorisé. Si vous avez reçu ce courriel par erreur, SVP en aviser immédiatement l'expéditeur et détruire le courriel de votre système. STRICTLY PERSONAL AND CONFIDENTIAL. This email may contain confidential and proprietary material for the sole use of the intended recipient. Any review or distribution by others is strictly prohibited. If you are not the intended recipient please contact the sender and delete all copies.

> Hi all, > > I have made an I/Q recording with a NI-USRP 2920, which includes a WBX > daughterboard (input signal is a CW) > > When I do a playback of my recording at Fc=1GHz, and gain at minimum > (0dB), I see the CW at -50dBm. > > I have switched the daughterboard of the USRP for a SBX. > > When I do the playback of the same recording at Fc=1GHz, and gain at > minimum (0dB), I see the CW, but now at -40dBm. > > Q: Is it normal that the SBX daughterboard generates signals 10dB > higher than the WBX daughterboard, when both are set to use the same > gain? Or is there a parameter in UHD that should be set differently > for the SBX daughterboard? > > I'm using an old version of UHD: 3.4.4 > > Thanks! > > Serge > These are analog upconverter cards, with different component line-ups. There'll be one or two dB difference between cards of the same type, even for the same settings. So having larger differences between cards of different types for the same settings doesn't surprise me at all. The gain setting *does not* set output to a fixed, calibrated level, it just controls a variable attenuator in the output stage, and the output stages are different, somewhat, between cards. One thing to note is that older WBX cards had a different TX gain setting mechanism in the hardware as well, which might also explain the 10dB difference. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org