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 !
this is FCO
this is DCO
this is dataout
The frequency of the output pulse looks consistent with shifting out 1000 0000, though the waveform does not look good. Looking at your "dataout" oscilloscope screen shot again from your previous…
Thank you for using the AD9287.
I agree with what you state from the AD9287 datasheet timing diagram.
Would you please double-check the signals you are probing? I believe it is impossible for FCO frequency to be greater than DCO frequency, and FCO frequency to be the same as the serial data output waveform frequency.
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!