CID Interconnect Modeling & Simulation 2

Question 1

In a transmission line SPICE model, what does the 'TD' parameter represent?

Accepted Answer

Propagation delay of the line

Answer

TD (time delay) specifies the one-way propagation delay of the transmission line, derived from length divided by the phase velocity.

Question 2

Which S-parameter is used to characterize the return loss of a two-port interconnect network?

Accepted Answer

S11

Answer

S11 represents the input reflection coefficient, and return loss is defined as -20·log10|S11|, measuring how much signal is reflected at port 1.

Question 3

What is the primary advantage of using W-element models over RLGC lumped models for high-speed interconnects?

Accepted Answer

Frequency-dependent loss and dispersion are accurately captured

Answer

W-element (lossy transmission line) models support frequency-dependent RLGC parameters, accurately capturing skin effect and dielectric loss at high frequencies.

Question 4

In electromagnetic simulation, what does 'de-embedding' accomplish?

Accepted Answer

Removes the effect of fixture or launch structures from measured data

Answer

De-embedding mathematically removes the influence of test fixtures, probes, or launch structures so only the DUT characteristics remain.

Question 5

A via stub resonance in a PCB causes signal integrity problems primarily because it creates:

Accepted Answer

A notch in the insertion loss at the stub resonant frequency

Answer

The unused via stub acts as a shunt stub resonator, producing a transmission null (notch) at the frequency where the stub length equals a quarter wavelength.

(CID) Certified Interconnect Designer Practice Test

(CID) Certified Interconnect Designer Practice Test

CID Interconnect Modeling & Simulation 2