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Original question:

AFE7444EVM: AFE7444EVM initialize problem

AFE7444: Set RX Frequency more than 2.9 GHz under mode 4

Dinuka Madushan
Prodigy 10 points
Part Number: AFE7444

Tool/software:

Hi,

I'm using AFE7444 in mode4 with DIV3(default). I need to set the RX_A Frequency to value greater than 2.9GHz (NCO>2.9).  I need to go up to RX frequency of 4.4GHz.

Can I achieve it just changing the DIV to /2?. I tried using EVM GUI to set to DIV to 2 and generate .cfg but i'm getting an error. 

I manually changed the register so I can get 4423.68MHz Fadc and I can see the Fadc correctly set by probing test point. But I couldn't receive data on FPGA side if I loopback Tx to Rx. 

Am I doing something wrong?

Thank you!

  • 0
    TI__Genius 17831 points

    Hi Dinuka,

    In order to update the NCO to a frequency above the sample rate there is no need to change the sample rate, which is a max of 3Gsps for the ADCs (as shown in the datasheet). Instead you can simply input the requested value into the Rx NCO field in the GUI. The ADCs in the AFE7444 support muli-nyquist operation and can therefore support the 10MHz to 6GHz range while utilizing the max Fs of 3Gsps. 

    Regards,

    David Chaparro