Problem with sampling via Visual Analog (AD9266-20 and HSC-ADC-EVALCZ)

Hello,

I am currently using the AD9266-20 Evaluation Board in combination with the HSC-ADC-EVALCZ and the Visual Analog Software. I seem to be having a problem with the correct acquistion of the data. On every record that I take the first 127 samples all have the same value and only after that the samples follow the sine-wave input (see picture). Even if I run continuously, the same problem occurs for every record.

Is there some setting that I forgot to adjust or is this a communication problem between the FPGA and the ADC?

Best regards

Lizzy