If the sampling rate of an oscilloscope is too low relative to the signal frequency, what artifact may appear?

• A. The waveform becomes red.
• B. The display becomes pixelated but accurate.
• C. The vertical resolution improves.
• D. Distortion due to aliasing can occur if the sampling rate is too low.

Answer: (D)

When the oscilloscope doesn’t sample fast enough, it can’t faithfully track the rapid changes of the signal. This leads to aliasing: higher frequency components fold into lower frequencies and the displayed waveform becomes distorted, even though the actual signal hasn’t changed. So the artifact you’d see is distortion caused by aliasing. The other ideas—color changes, pixelation with accurate display, or improved vertical resolution—don’t reflect what happens when sampling is too slow. Increasing the sampling rate or adding an anti-aliasing filter helps prevent this distortion.