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Observer
Observer
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Registered: ‎10-11-2018

Noise like spur at ZCU111 ADC

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Hello.

 

I'm using ADC at following setting.

  •  Fs = 3932.16MHz(Internal PLL is bypassed)
  • Decimation=8x
  • Mixer Freq. = 491.52MHz

 

Check ADC spectrum not receiving signal via RF Analyzer, ADC appears to receives noise(up to about -90dBm) at 0 MHz as picture.

ADC.png

 

I have 2 questions about this.

  1.  Who knows the cause of this noise?
  2.  Is there a workaround?

 

Best regards.

 

 

 

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Moderator
Moderator
260 Views
Registered: ‎08-08-2017

Re: Noise like spur at ZCU111 ADC

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Hi @kikd180 

It seems you are only capturing noise , Try to give the valid single tone/dual tone or Modulated signal and observed the spectrum.

With the noise only , ADC Callibration is not converging and Spurs are expected.  Please refer to ADC calibration mechanism section  in our IP  product guide for more 

detailing.  page 53

https://www.xilinx.com/support/documentation/ip_documentation/usp_rf_data_converter/v2_2/pg269-rf-data-converter.pdf

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Moderator
Moderator
261 Views
Registered: ‎08-08-2017

Re: Noise like spur at ZCU111 ADC

Jump to solution

Hi @kikd180 

It seems you are only capturing noise , Try to give the valid single tone/dual tone or Modulated signal and observed the spectrum.

With the noise only , ADC Callibration is not converging and Spurs are expected.  Please refer to ADC calibration mechanism section  in our IP  product guide for more 

detailing.  page 53

https://www.xilinx.com/support/documentation/ip_documentation/usp_rf_data_converter/v2_2/pg269-rf-data-converter.pdf

-------------------------------------------------------------------------------------------------------------------------------
Reply if you have any queries, give kudos and accept as solution
-------------------------------------------------------------------------------------------------------------------------------

View solution in original post

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Observer
Observer
223 Views
Registered: ‎10-11-2018

Re: Noise like spur at ZCU111 ADC

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Hello @pthakare 

 

Thank you for reply.

I tried give modulated signal.
And after a few seconds, I changed calibration state to "Freeze".

Noise was reduced than ADC receive no signal.

 

calib_frozen.png

 

Best regards.

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