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FMCOMMS2 with KC705 and Microblaze ADC values are saturated

Question asked by BenG on Apr 7, 2014
Latest reply on Apr 10, 2014 by BenG

I'm using the No-OS project for the FMCOMMS2 targeting Microblaze on the KC705. My ADC values in ChipScope always indicate a saturated full scale input when I input an RF tone, regardless of input signal strength. I have input a tone offset by 1 MHz from the RX LO Frequency for signal strengths from -30 to -90 dBm. Chipscope indicates the correct frequency, but the signal amplitude is always full scale. I have changed the input frequency and confirmed the change via ChipScope.

 

I have also modified the gain control (GC) modes, and setting manual gain improved the ADC samples so that the samples are less saturated, but they are still at full scale.

 

Do I have to modify some settings to show a reduced level input signal? If so, which ones?

 

Ben

 

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