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FMCOMMS1 Harmonics

Question asked by luca.cucchi on Aug 6, 2015
Latest reply on Aug 19, 2015 by charlyelkhoury

Hi,

I'm using the FMCOMMS1 mounted on the ZC706 in order to acquire baseband complex signal.

Basically I bypass the RF and the demodulator section of FMCOMMS1 and I provide directly in J11&J13 with complex GSM-like signal coming from an Agilent Baseband signal generator with 3 MHz frequency offset.

As you can see (in the attached figure) IIO Oscilloscope displays other replicas in addition to the highest correct one.

Furthermore you can notice a very high DC offset.

 

Could you please explain those effects ? Could you suggest any procedures to reduce both of them ?

 

I've set the sampling frequency to about 54 MSps, and I've disabled the LO oscillator and the TX chain. I've tried to use the calibration panel of IIO Oscilloscope but with no improvements.

 

Thank you

Regards

Luca

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