Digital systems have strict requirements for timing. In order to meet the requirements of the signal timing, adjustment of the signal wiring on the PCB has become part of the PCB design work. Adjusting the wiring length includes two aspects: relative and absolute.

　　The so -called relative is that the length of the wiring is consistent, and ensure that the signal is synchronized to several receivers. Sometimes there is correlation between a set of signal lines on PCB. For example, the bus needs to be corrected, because the signal needs to be synchronized at the receiving end. Its adjustment method is to find out the longest wiring, and then adjust other wiring to the equal length.

　　The absolute requirement is to control the delay of the wiring between the two devices to a certain value, such as the delay between the device A and B as the ins, and this requirement is often proposed by the high -speed circuit designer, and the PCB engineer will realize it. Essence To meet this requirement, it is necessary to know the transmission speed of the signal. However, it should be noted that the signal transmission speed is related to factors such as the material of the PCB, the structure of the wiring, the width of the wiring, and the perforated. Knowing the speed of signal communication, you know the required wiring delayed routing length.