Tool/software:
Hello,
I have AMD/Xilinx ZCU111 kit which uses the LMK04208 as clock jitter cleaner and to provide clock for the FPGA and the DAC/ADC components. By default, the kit uses CLKin0 to receive a reference clock using a TCXO 12.8 MHz on the ZCU111 kit.
In my setup, I want to synchronize the ZCU111 kit with an external instrument that generates a 10 MHz reference clock. To do so, I have configured the LMK04208 to use CLKin1 for which I provide a single-ended 10 MHz generated by the reference clock on the SynthHD Pro v2.
Here is a snapshot depicting the 10 MHz clock from the SynthHD Pro. At the output of the generator, I have added DC Block + 3 dB attenuation to ensure AC coupling and meet the specs for the swing.
This is the configuration that I have applied in the TICS Pro to switch to CLKin10 and configure the system to use 10 MHz.
As you can see from the figure above, I configured CLKout5 to generate a 40.28 MHz clock signal and I feed this clock to the scope.
To validate the synchronization, I added a two-way power splitter at the output of the 10 MHz. I feed one output to the ZCU111 kit and the other one to the scope.
On the scope, I chose the channel fed with 10 MHz as my source for the trigger, however, I see the trigger does not affect the channel which is connected to the CLKout5.
This is a clean indication that the input 10 MHz is not in sync with the 40.28 MHz signal. Here is a snapshot from the scope including both the 10 MHz and the 40.28 MHz clocks.
Is there anything I am missing in the configuration of the LMK04208? Are there extra knobs that I must enable?
Thanks.
