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ADC12D1000: Harmonic amplitude too large for ADC12D1000

Mickey Zhang
Genius 12080 points

Part Number: ADC12D1000

hHi team,

The customer uses ADC12D1000. Sampling rate is set to 2GHZ. The input signal frequency is 30MHz. 

Use I/O parallel configuration mode. Add 30M bandpass to the input port. 

The customer uses waveVision to import the data which is captured by FPGA and uses the matlab to analyze the data. 

He found that  the  amplitude of 2nd and 3rd harmonics is too  large. The power  clock and the input signal is fine. 

Please check the attach. They are the data in the  waveVision and the matlab.

Would you explain why the  amplitude of 2nd and 3rd harmonics is too  large?

  • 0
    TI__Mastermind 44680 points
    Hi Mickey
    The most likely issue is that the bandpass filter doesn't have sufficient rejection of the harmonic frequencies of 30 MHz. Can the specifications of the filter be provided?
    There could also be some problem with the signal path between the filter and the ADC inputs that is degrading the harmonic performance. Can the schematic from single ended signal input to differential ADC inputs be provided?
    The final possibility is that the ADC calibration is not optimal. An on-command calibration should be performed after the ADC is powered-up, configured and clocked and has reached a die temperature near the final operating temperature.
    Please investigate these different possibilities with the customer.
    Best regards,
    Jim B
  • 0 in reply to Jim Brinkhurst1
    TI__Mastermind 44680 points
    Hi Mickey
    Do you have any update on this from the customer?
    Can the raw data file be shared so I can analyze in HSDC Pro myself?
    Best regards,
    Jim B