Dual tone spurious emission


I require -55dBc spurious suppression for a dual tone signal, separated by 20Mhz.
For LMS6002 i have measured ~-50dBc for TX and -40dbC for RX. Here is a measurement for TX:

It is impossible to further reduce I/Q imbalance spurs, because two tones require different compensation values. So it seems that LMS6002 does not fit my needs.

I am interested about LMS7002 performance regarding this matter. Has anyone tested this before? Datasheet promises -55dbc max, but what are the real life numbers?

Thank you!

Hi @Zortz,

Make sure you are setting IQ interleave and poliarity correclty. Thismight affect your IQ cal if set incorrectlly. The calibration result should be better then - 55 dBc on boath sides.


Hi @RicardasVadoklis,

Could you please reassure that i should see -55dBc on both sides for dual tone separated by 20Mhz?
I am sure that IQ interleaving and polarity is handled correctly.


We have multiple people in bladeRF community with this issue. That is -50 dBC for TX and -40dBc for RX. These results are for dual tone signal with 20Mhz separation, reducing the separation gives better results. We can almost perfectly tune out images at 3M separation. Problem gets worse as the band increases.
Here is an image for RX side:

Do you have an phase-response plot for the LPFs, similar to magnitude response curves in Figure 6 of the datasheet?

Thank you for your answer and time :sunny: