hi, I am trying to estimate noise power without injecting any signal in SBX board with USRP N210. 1. Carrier frequency is 2.452GHz with BW of 10MHZ. 2. Gain = 0dB and using Tx/Rx port. noise power = (sum of 64 samples of amplitude squared)/64. I am getting around -78 dB. If I try to evaluate dBm/Hz, I am getting -78 - 70 = -148 dB/Hz. Hence , it will be -118 dBm/Hz. Its not matching with theoretical value of -174 dBm/Hz + 5 dB = -169 dBm/Hz. Where am I going wrong with my calculations? Thanks sencen

There are no units on those samples. You need an absolute amplitude reference in order to determine the volts to number conversion. Matt On Mon, Feb 18, 2013 at 5:33 AM, senthil murugan <amrita.senthil@gmail.com>wrote: > hi, > > I am trying to estimate noise power without injecting any signal in SBX > board with USRP N210. > > 1. Carrier frequency is 2.452GHz with BW of 10MHZ. > 2. Gain = 0dB and using Tx/Rx port. > > noise power = (sum of 64 samples of amplitude squared)/64. > > I am getting around -78 dB. If I try to evaluate dBm/Hz, I am getting > -78 - 70 = -148 dB/Hz. Hence , it will be -118 dBm/Hz. > > Its not matching with theoretical value of -174 dBm/Hz + 5 dB = -169 > dBm/Hz. > > Where am I going wrong with my calculations? > > Thanks > sencen > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > >