Any one of the traces on the PCB when the signal will be caused by the delay in the case of a high frequency signal , the main role is to compensate serpentine traces " of the same set of related " a small part of the signal in the delay line , these portions or is usually not less than the other signals processed by additional logic ; most typical is the clock line , which normally does not need to go through any other logical process , and thus the delay would be smaller than the other related signals.
PCB boards and other high-speed digital line length is to make the delay difference of the signals remain within a range, to ensure the effectiveness of the system in the same cycle to read data ( delay difference would be wrong to read the next cycle when more than one clock cycle data ) , generally require a delay difference does not exceed 1/ 4 clock cycles per unit length of the line delay difference is fixed, the delay with the line width, line length, copper thickness , lamellar structure related, but the line is too long will increase the distributed capacitance and distributed inductance , so that the signal quality , the clock IC pins are generally connected RC termination , but not from the serpentine trace inductance effects , on the contrary , would signal the rise inductance element in the high-order harmonic phase shift , resulting in the deterioration of signal quality , it requires at least twice the serpentine line spacing width , the smaller the rise time of the signal more susceptible to distributed capacitance and inductance.
Because different applications have different effects , if serpentine traces appear in the computer board , which has played a major role in the filter inductor to improve the circuit 's noise immunity , computer motherboards serpentine traces , mainly used in Some of the clock signal , as CIClk, AGPClk, which has two effects : one , two impedance matching , filter inductor. Some important signals, such as INTEL HUB architecture HUBLink, a total of 13 , running 233MHz, requirements must be strictly equal length , to eliminate hidden dangers Delays caused by the winding is the only solution. In general, the serpentine traces line spacing > = 2 times the width. Hunting line PCI board is to meet requirements of PCI 33MHzClock of line length . If an ordinary PCB board , is a distributed LC filter parameters , but also as a radio antenna coil, short and narrow serpentine traces fuses do so .
