A bus interface is an output only from a chip at 50 MHZ , 3.3V LVTTL. The target unit receives this data. I heard of some methods used to adjust voltage thresholds and timing on the target based on a comparison of specific test patterns. If the test patterns fails, adjustments to thresholds on timing are made until the comparison is a match. The bus signals need to get to an FPGA in the target. Specifically in hardware, what techniques have people used to accomplish this ? Can it be done directly in the FPGA or should it be some special buffer or analog circuit to make this adjustments?