Practice Test GeeksPCB - Design Practice Test
← All PCB Flashcard Decks

Signal Integrity & EMC Flashcards

7 cards from real PCB practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Signal Integrity & EMC flashcards as text

  1. What is the industry-standard characteristic impedance target for most controlled-impedance PCB traces?

    Answer: 50 ohms

    50 ohms is the industry-standard characteristic impedance used to match source and load impedances, minimizing reflections on high-speed traces.

  2. What phenomenon occurs when a high-speed signal travels down a transmission line and encounters an impedance discontinuity?

    Answer: Signal reflection

    Reflections occur at impedance discontinuities because signal energy that cannot pass through the mismatch is sent back toward the source.

  3. Which termination method places a resistor matching the trace's characteristic impedance between the signal line and ground at the far end of the trace?

    Answer: Parallel (shunt) termination

    Parallel termination places a resistor equal to the characteristic impedance to ground at the load end, absorbing reflected energy and preventing signal bounce.

  4. At what fraction of signal wavelength does a PCB trace typically need to be treated as a transmission line requiring controlled impedance?

    Answer: λ/10

    Traces longer than 1/10 of the signal wavelength (or equivalent rise-time length) must be treated as transmission lines to avoid signal integrity problems.

  5. In a stripline PCB layer configuration, where is the signal trace located within the stackup?

    Answer: Between two reference planes

    Stripline traces are embedded between two ground or power reference planes, providing shielding on both sides and superior EMI performance compared to microstrip.

  6. What is the primary signal integrity advantage of differential signaling over single-ended signaling in high-speed PCB design?

    Answer: Superior common-mode noise rejection

    Differential signaling rejects common-mode noise because interference coupled equally onto both signal lines cancels out at the differential receiver.

  7. Which instrument is used to measure the impedance profile of a PCB trace as a function of distance along its length?

    Answer: Time Domain Reflectometer (TDR)

    A TDR sends a fast-rise-time pulse down the trace and measures reflections over time, revealing impedance variations and discontinuities along the trace.