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4

This isn’t a solution to your problem, but I had similar challenges with UHF RFID at 865 MHz. In UHF RFID the tags are electrically short dipoles modulated by the chip impedance. I thought it would be impossible to measure the two way traffic due to the huge difference in the TX and RX signal amplitudes. I solved this by making a tiny hole through the tag ...


2

Check my project at https://github.com/josevcm/nfc-laboratory Regards Jv


0

The edges of your spectrum is where the performance of the receiver is hitting the limit. there is a trade-off between flatness and total bandwidth. they could have made the bandwidth smaller to keep it nice and flat but figured, a little extra bandwidth might be nice to have. It's not like this is a spectrum analyzer.


0

Answer to part 2: The USRP SDR uses an downconverting IQ modulator before the ADCs. An error in quadrature phase or quadrature levels of the two IQ modulator clock signals or gain and delay balance of the IQ modulator(s) can result in DC artifacts in the spectrum of the IQ ADC data. The ADCs themselves can have a small DC offset in their sampling. Both of ...


-2

Answer to your first question: As far as I know, the USRP device that you use has a maximum gain of 30 dB. So, I recommend you decreasing the gain a little. Second one: As you may know, the USRP devices firstly amplify and downconvert the received signal, then sample it. The two first RF stages have a part called "DC choke (maybe RF coupling) " ...


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