Simulation or Measurement
When designing a PCB, it is important but difficult to make sure the finished goods fabricated as per your design can work both correctly and smoothly. So we are used to doing some functional test and checking the performance during the design process, and it is common to find some problems. At this time, if you have to choose between board simulation and board measurement, you’d better to make time for both.
Most people would be used to measuring their boards only, because that will always be the closest to reality. But that is not always the case, especially with the fast busses used on PCB designs today. Edge rates are so fast that measuring the actual system is not practical, because measuring inner chip to get an accurate view of the performance is also very crucial. But measurements need to be taken on test boards or with special test fixtures, which may not represent the actual system. And this is where simulation is indispensable, because it can allow you to look in places the probes can’t touch.