I want to know how to be sure of my design that it will take the certificate,
- if you mean how to be sure if your board will pass the certification process, then, do some measurements before. You can go to a test house specialized for certification and ask them just to measure your board / product. Just measuring your boards is much cheaper then paying for the whole certification. If your product passes all the measurements, then you will get confidence, that it will also pass the certification process.
what is the previous steps before take the boards to the testing house.
- prepare your setup at your lab. When you will be in the test house, the time will be very expensive. So,
before you go to the test house, be sure you test all your setups, hardware, software, connections, ... be sure you know exactly what you would like to try (with a box, without a box, with 0R resistors, with capacitors, different cables - cables can make BIG difference, different power adapters, etc) ... be sure everything is running every time you build your setup.
PS: these can give you and idea what we did during EMC testing:
- TinyRex:
https://www.imx6rex.com/imx6-tiny-re...n-emc-testing/- OpenRex:
https://www.imx6rex.com/open-rex/sof...x-emc-testing/-
https://www.imx6rex.com/?s=emc&submit=Search