A method for skew-free distribution of digital signals using matched variable delay lines

We have presented a novel technique that allows skew-free distribution of digital signals with known and controllable arrival times. The technique requires adjustments and measurements only at the sender. Our method is based on measuring the round trip delay of a signal and then adjusting it with a pair of matched delay lines. This technique can be modified to work without extra wiring, and is effective for receivers along as well as at the end of a wire. This method can be readily implemented using well-known circuit forms in ECL and CMOS technologies, and incorporates well into the boundary scan logic of a custom VLSI chip.