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AD9234 clock frequency variation - Vary frequency from 800 MHz to 1 GHz?

Question asked by Lionelwallace Employee on Jan 14, 2016
Latest reply on Jan 16, 2016 by UmeshJ

I received this customer question

 

I am trying to understand the requirements for the clock signal for the AD9234

  • We plan to vary the clock constantly from 800MHz to 1000MHz while we collect a set of 2048 samples.
  • The datasheet states that the clock duty cycle should not vary more than 5%.
  • While we are speeding up the clock rate from 800MHz, that means the clock frequency will only vary about  0.025% per sample.
  • After collecting about 100 samples, we have sped the clock up to 820MHz, which means the clock duty cycle has changed a total of 5% since we collected the first sample at 800MHz.
  • After collect 1024 samples, we will begin decreasing the clock pulse frequency from its peak at 1000MHz.
  • Now, after collecting another 125 samples, we have slowed the clock down to 975MHz, which means the clock duty cycle has changed a total of 5% since we collected the sample at 1000MHz.

 

  • Does this moderately slow change to the clock pulse frequency affect the performance of the ADI AD9234?
    • If so, how?


Also, If I understand correctly, in order to use the full 1000 MSPS then you must use all output lanes for one set of samples. Please confirm.

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