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Question for your AD-FMCOMMS1-EBZ

Question asked by Kaos on May 6, 2015
Latest reply on May 7, 2015 by Kaos

Dear Sir/Madam,

 

 

We are proceeding our job with your AD-FMCOMMS1-EBZ. 

So we have the following questions.

We still cannot catch the reason why this trouble comin from.

 

We have inputed the AM modulated signal that is 400MHz carrier and 1MHz base band via 10dB / 20dB external attenuator to AD-FMCOMMS1.

So we enclose the scope pictures the spectrum analyzer ,the FFT and constellations of IIO-oscilloscope as follows.

 

attenuator=10dB

AM_spectrum_Attnuator10dB.png

IIO_spectrum_Attnuator10dB.png

IIO_Constellation_Attnuator10dB.png

 

attenuator=20dB

AM_spectrum_Attnuator20dB.png

IIO_spectrum_Attnuator20dB.png

IIO_Constellation_Attnuator20dB.png

 

The external spectrum analyzer show AM wave form when attenuator is 20dB.

But please advice us the reason why the IIO-oscilloscope(FFT spectrum) show like a DSB wave form spectrum and also the constellation close the DSB wave form.

 

And when the attenuator is 10dB, the FFT spectrum on IIO oscilloscope show AM wave form we think but the constellation have the  much offsett. Why this comin?

 

Thanks a lot Kaos

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