High speed PCB design, should from those aspects to consider EMC, EMI rules?

 The general EMI / EMC design requires the simultaneous consideration of radiation ( radiated ) and transmission ( conducted ) two. The former belongs to high frequency ( > 30MHz ) portion of the latter is the low frequency part ( < 30MHz ). So not only pay attention to high frequency and low frequency part of neglect. A good EMI / EMC design must be a beginning of the layout time must consider the position of a device, PCB laminated arrangement, important online method, device selection and so on, if they didn't have preferred arrangement, after the settlement is perceptibly, increased cost.
 For example, a clock generator position as far as possible not to close to the external connector, high speed signal to go inside and pay attention to characteristic impedance matching with the reference layer continuous to reduce reflections, device the signal slope ( slew rate ) as small as possible in order to reduce the high frequency components, choosing to coupling ( decoupling / bypass ) capacitor when the attention of its frequency response is to meet the demand to reduce power supply layer noise.
 In addition, pay attention to high frequency signal current return path so that the loop area as small as possible (that is, the loop impedance loop impedance as small as possible ) to reduce the radiation. Can also use segmentation formation to control high frequency noise range. Finally, the appropriate choice of PCB and the outer shell of the ground ( chassis ground ).