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I am working with BladeRF xA4.

I have a signal generator at 1.5GHz modulated with cos(2pif_mt)+jsin(2pif_m*t). This generator is conected to a signal splitter. Next to the splitter two cables are connected to two inputs of the BladeRF.

I acquired the waves with:

status = bladerf_sync_rx(dev_, &arr_, READ_SAMPLE_SIZE, &meta_, BLADERF_RX_TIMEOUT_MS);

meta_=NULL; //BLADERF_FORMAT_SC16_Q11

https://nuand.com/libbladeRF-doc/v2.2.1/group___s_t_r_e_a_m_i_n_g___f_o_r_m_a_t.html

arr_ is a an array of complexes int16. std::arraystd::complex<int16_t

arr_[0] , RX1

arr_[1], RX2

arr_[2], RX1

I just plot the values and gives the plot in attach.

The signals instead to be equal, the second signal seems to have the I and Q exchanged.

Could anyone give a clue on this?

Thanks,

Luís Gonçalves

Two RX Signals

Luis Gonçalves
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  • What is more worrying is that in RX2 the phase between I and Q is not pi/2. I'd say the problem is I/Q imbalance. – MBaz Feb 09 '23 at 14:31
  • We have several boards and all have this problem. – Luis Gonçalves Feb 10 '23 at 10:40
  • You may have better luck here: https://www.nuand.com/forums/ Also, there's a ton of support info for these devices on their github wiki page: https://github.com/nuand/bladeRF/wiki – MBaz Feb 10 '23 at 17:43
  • None of these problems are refered in it. And the forum is not accepting new posts for a long time. – Luis Gonçalves Feb 11 '23 at 18:33
  • RX1 seems that was aligned by factory (AD9361 align by Analog Devices or Nuand align with FPGA settings). RX2 seems completly unaligned. – Luis Gonçalves Feb 12 '23 at 03:35
  • I'm sorry I can't be of more help... I don't have a lot of experience with the BladeRF. – MBaz Feb 12 '23 at 17:10

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