To ensure accurate digital representation in OCT, sampling frequency should be at least how many times the highest frequency component?

• A. 1.0 times
• B. 2.0 times
• C. 4.0 times
• D. 2.3 times

Answer: (D)

In digital sampling, you must sample at a rate at least twice the highest frequency present in the signal to avoid aliasing. In OCT, the axial information is carried by high-frequency content that corresponds to the finest depth features, so you’d want a sampling rate that comfortably covers that content. While 2× the maximum frequency is the theoretical minimum (Nyquist), real systems have nonideal anti-aliasing filters, detector limitations, and reconstruction considerations that mean a small safety margin is wise. Using about 2.3× the highest frequency component provides that margin, helping ensure accurate digital representation of the OCT signal. The other options either undersample, waste bandwidth, or barely meet the theoretical limit without accounting for practical factors.