Which of the following does not bebng to the U1900 cabling specifications?

Question

Options

• AThe PGND cable is grounded based on the nearby principle, and is properly connected to the
• BThe length of the PGND cable does not exceed 45 cm. The PGND cable shall be as short as
• CThe PGND cable shall not be in parallel or twisted with signal cables.
• DSignal and power cables are separated, and analog and digital signal cables are routed together.

• A
  10% (3)
• B
  7% (2)
• C
  3% (1)
• D
  79% (23)

Explanation

Option D violates proper cabling practice because analog and digital signal cables should be routed separately, not together. Mixing them causes electromagnetic interference and signal degradation - digital switching noise can corrupt sensitive analog signals. The correct specification requires that analog and digital cables maintain physical separation just as signal and power cables do.

Options A, B, and C are all valid U1900 PGND (Protective Ground) cable requirements: grounding at the nearest point (A) minimizes impedance; keeping the cable under 45 cm (B) reduces resistance and inductive reactance; and avoiding parallel runs with signal cables (C) prevents ground loops and noise coupling. All three reflect legitimate EMC (electromagnetic compatibility) best practices that belong in the specification.

Memory tip: Think of cabling as a "like with like, but not all alike" rule - power stays with power, but when it comes to signal cables, analog and digital must always be kept apart. If an answer groups analog and digital together as if they're equivalent, it's wrong.

No community discussion yet for this question.