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Measuring AD9656's Frequency response

Question asked by fineconcerto@neusoft.com on Sep 25, 2017
Latest reply on Sep 29, 2017 by fineconcerto@neusoft.com

Hi Everyone,

 

I am measuring the AD9656's frequency response according to AN742, page4. My question is regarding the network analyzer's sweep time.

If I am setting the clock to 1Mhz or even lower, even with 90% duty cycle, I have only about 10us to 20us @ either Track mode or hold mode for the ADC. ( I guest AN-742 suggest 90% duty cycle, in order to increase the time for measurement? yes?)

 

I tried on my two network analyzers, THe first is Keysight, E5063A, the maximum BW is only 330Khz, hence two  sweep points will require at 353us. My second device is Rhode Swarhz ZNB4, which can sweep one ponit at around 1.7us( if I set the RBW to 1Mhz).

 

Here comes the question, how can I only capture 8-10 points ranging from 2Mhz to 200Mhz to test the ADC's frequency response with network analyzer? Does ADI use the same method as introduced in AN-742? If yes, then how can we set the network analyzer to sweep ultra fast?

 

Best regards,

Tangji

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