Re: [Discuss-gnuradio] Different amplitude on two USRPs

[mleech]

On Tue, 22 May 2012 22:40:11 +1000, Jamie Wo wrote:

Hi all,

I met a werid problem when receiving. When I ran 'rx_samples_to_file' example to receive signal from a signal source, e.g. radio station, on two USRPN210s, the amplitude of received signals are different, seen from gnuplot. 

Does anyone know why this happenes? I guess this is the problem of USRP, because I ran the same program, set the same parameters for 'rx_samples_to_file', receive the same signal source and the two USRP N210s were placed next to each other on the table. 

Is there a way to set USRP/daughterboard so that the received signals have the same amplitude on two USRPs or adjust other parameters in gnuradio/uhd to do that? 

Regards,

Jamie

Analog electronics can have variability in gain response, perhaps as much as 2dB for nominally-identical daughter-cards, and identical gain settings.

Furthermore, propagation can often lead to variations in signal strength between two identical receivers, with identical antennae even in the same physical area, especially in the presence of multi-path signal propagation.