Where to measure the signal in between the transmission line?

[zahrein]

HI Guyz,

Correct me if am wrong. In a motherboard there are a lot of transmission line. In one of the transmission line there is a capacitor between it. Let say the transmission line from the PCIE slot and ICH(Input output controller hub). There is a capacitor in between. So the function of the capacitor is to allow AC signal to pass through?

If i want to to measure the signal, at which point should i measure in between the transmission line. Let say the ICH is the transmitter and the Receiver is the PCIE slot.

Thanks

 

[FaZeng]

Transmission Line

The decoupling caps in your post is to use for isolating DC voltage and leaving AC signal for PCI-E signals. They should be put as near as possible to close the receiver side for the better disintegrating effect. In your case, you can measure the PCI-E signals via the PCI-E slot. However, it is more suitable to measure PCI-E signals for PCI-E add-on cards near the ICH.