USRPN210r4 with SBX
I am observing a strong spike at the center of the receive spectrum when I start burst transmission.
My top flowgraph contains following two hierarchical blocks
1) A transmitter flow graph with (tx_time, tx_sob, tx_eob)
2) A receiver flow graph
When I run top flowgrpah (without transmitting anything) and observe the FFT of the received signal the spectrum does not contain high spike in the center.
But as soon as I start transmitting in burst mode I see a very high spike in center of the received signal FFT spectrum. It looks like LO (transmitter or receiver ) is being received? Which one is it ? And why is it happening? How can I avoid it because it is affecting my packets.
When I apply the offset in digital using DDC/DUC, the spike moves out of the band.
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Bob