Hi, Checkout the USRP measurement pointed by :
http://www.nabble.com/USRP-Dynamic-Range-and-8-Bit-Problem-to14471573.html#a14484747 May be it will answer some of your questions. Keep in your mind that USRP is not a measurement device. It is an SDR peripheral device. If you want to use it as a measurement device, you should use a calibration method to modify its output to fit into your requirements. Regards, Firas Brook Lin wrote: > > Hi All, > > I found one of replies sent by Eric said that: > >>What are the units of the Y axis of usrp_oscope? > >>They are the output of the digital down converter. >>They are not calibrated to any particular voltage level. >>The levels depend on the gain setting too. > > My first question now is whether the red and blue lines on the oscope are > the numbers which are the 12-bit output of the ADC multiply the > sine/cosine @ IF? Eric said that the levels depend on the gain setting > too. If the gain is 0, do these show the actual signal receving by the > USRP in time domain? So the Y-axis should be mV when gain is 0, right? > However, I don't think the gain and the output are linear. How does the > gain effect the output of the DDC? > > My second question is when gain is 0, usrp_fft.py shows the actual signal > in frequency domain, and Y-axis are in mdB. Am I right? What is the 0dB in > fft? Is it exact 0 or some reference number? > > Thanks, > Brook > -- View this message in context: http://www.nabble.com/Questions-on-DDC-output-tp14897066p14948024.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
