AD9287 Dataout frequency not right

I  have gotten a problem with AD9287ABCPZ-100, as follows,

According to the Timing diagram of AD9287 ,when my input  clock is 20Mhz, the frequency of dataout should be 80Mhz ,and the bit clock(DCO) should be 80Mhz ,frame clock(FCO) should be 20Mhz .

But in fact ,the frequency of DCO and DCO is right ,but the frequence of dataout is 20Mhz,too. So it makes me confused ,Idont know which question leads to this. SO I need a help.

Thanks for your answer !

Parents Reply
  • Thanks for your patient reply. In fact ,I check the data signals, then I find that when my analog input is equal to 0, the frequency of data_out is equal to FCO, while even if it is not 0, the frequency of data_ out  is  higher ,but I  can't tell it's eight times the frequency of the FCO. Here is the diagram that analog input is not equal to zero when FCO = 20Mhz.Thank you!

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