I'd like to be able to look at the output of the LNA in the AD9361 Simulink model. I've been able to modify the model to get the output from the IQ demod, but no further back towards the receive antenna. The issue is that when I take the output from the LNA, I still get the spectrum from roughly -5.5 to +5.5MHz. I'm not sure how to set the spectral display. It seems that the issue is with the inherited sample rate in the spectral display, but I don't see how to adjust that.
One other question. In the LNA, I see that NF (noise figure) is used as a variable to set the noise contribution of the LNA, but I don't see where in the model where NF is actually defined/quantified.
The model takes into account the non-idealities present in the process of converting real passband signal to complex baseband, but doesn't actually implement this step.
In fact, if you select Display->Signals & Ports->Port Data Types, you will see the data types of the various signals connecting the blocks. You will find that the input going into ad9361_RX in the top level view of the model is of type complex double.
OK, thank you again for the quick response. I'm looking at the output of the LNA, and have the oversampling rate set to 1.5 (default), so looking at +/-5MHz. I see nothing but noise at the LNA output, same at the LNA input. I can see the 2 MHz RF in the baseband spectrum analyzer, but I don't see it in the signal chain until after the demod.
Hi Srikanth, any thoughts on why I'm seeing only noise at the LNA output, no 2MHz signal, even though I see the 2MHz on the demod output?
Hi Steve, sorry for the delay. Double-click the Outport block that is connected to the output of the LNA and set the carrier frequency to 2 GHz, the LO frequency used at the top-level of the ad9361_RX block. This will show the 2 MHz signal.