pcb design you may encounter three kinds of problems
In general, the three power supply were done in the three, the signal quality is better. Because it is unlikely that the signal across the plane layer of the phenomenon. Cross-segmentation is a factor that is critical to signal quality, and simulation software generally ignores it. For the power plane and the formation, the high-frequency signal is equivalent. In practice, in addition to considering the signal quality, the power plane coupling (using the adjacent ground plane to reduce the power plane AC impedance), stacked symmetry, are the factors to be considered.
2, PCB at the factory how to check whether the design process requirements?
Many PCB manufacturers in the PCB processing to complete the factory, have to go through the power of the network off test to ensure that all the correct line. At the same time, more and more manufacturers also use x-ray test, check the etching or laminating some of the failure. For the finished product after the patch processing, the general use of ICT test and inspection, which requires PCB design to add ICT test points. If there is a problem, you can also use a special X-ray inspection equipment to exclude whether the cause of processing failure.
3, "the protection of the agency" is not the protection of the case?
Yes. The cabinet should be as tight as possible, with little or no conductive material, as much as possible.