Aspects in Which There is Similarity between High Speed and HighFrequency PCBs

There is a point regarding the definition of high-speed PCBs: a high speed PCB is a circuit board that consists of digital circuit speed at or above 45 to 50MHZ, and for more than one-third of the entire systems is accounted by digital circuit signals. But this definition of high-speed PCB is not fully correct. In case you take it for granted, and when you are doing a PCB project whose maximum signal speed reaches 49.9MHz, you will feel relaxed as this is not a high-speed PCB and keep moving on. At last, the PCB fails, the delivery has to delay, and you miss the expected bonus. The meaning of high speed and high frequency is different but Express PCB and high-frequency PCBs are the same printed circuit boards. The sine wave is the carrier of modulated signals. A high-speed circuit indicates that in a short period the voltage rises or drops, and a high-frequency circuit says that the circuit cycle is short (frequency is the reciprocal of the period).