Aliasing occurs when high-frequency components masquerade as lower frequencies due to insufficient sampling. How can it be mitigated in telemetry systems?

• A. By applying an anti-aliasing filter and selecting an appropriate sampling rate.
• B. By increasing the data encoding complexity.
• C. By decreasing transmitter power to reduce noise.
• D. By using longer packet headers.

Answer: (A)

Aliasing happens when frequencies higher than half the sampling rate sneak into the measured spectrum because the sampling is too slow to capture the signal’s details. To avoid this in telemetry, you need to control the signal content before it’s sampled and choose a sampling rate that can faithfully represent it. The standard solution is to place an anti-aliasing filter, a low-pass filter, in front of the analog-to-digital converter to remove frequency components above theNyquist frequency. Then set the sampling rate at least twice the highest frequency you care about in the signal, with some margin to account for filter imperfections and practical tolerances. This combination prevents high-frequency content from folding into lower frequencies and allows accurate reconstruction of the original signal at the receiver.

Increasing encoding complexity doesn’t address the spectral content that causes aliasing, reducing transmitter power doesn’t remove high-frequency components, and longer packet headers don’t affect the sampling process or spectral content.