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
  • Hi Doug,

    I just followed your instructions,and these are the waveform I got. Are they right?

    The sample frequency is 20Mhz. So the cycle is 50ns, the waveform shows below means 1000,000 ?

    The first picture is the waveform of D+A minus D-A, and the second is D+B (-) D-B.

    In fact, only the first ADC is used, and the other ADCs' pins are suspended.

    So their amplitude are not same ? 

    Thanks for your reply!