The primary tradeoff when selecting Pulse Repetition Frequency (PRF) is:

The primary tradeoff when selecting Pulse Repetition Frequency (PRF) is:

• A. Ambiguity in range versus ambiguity in velocity
• B. Pulse width versus dwell time
• C. Sensitivity versus resolution
• D. Power versus cooling

Answer: (A)

The primary concept here is how Pulse Repetition Frequency sets what you can measure without ambiguity in both range and Doppler velocity. A higher PRF makes the Doppler (velocity) measurement unambiguous over a larger range of speeds, but it reduces the unambiguous range because the maximum distance that can be measured without range ambiguity is c/(2×PRF). Conversely, lowering PRF expands the unambiguous range, but increases the chance of velocity aliasing, since the maximum unambiguous velocity is proportional to PRF (roughly V_unambiguous ≈ PRF × λ/4). So the main tradeoff when selecting PRF is between ambiguity in range and ambiguity in velocity. In practice, operators choose PRF to balance expected target speeds and ranges, sometimes switching PRFs or using multiple PRFs to resolve both ambiguities.

The primary concept here is how Pulse Repetition Frequency sets what you can measure without ambiguity in both range and Doppler velocity. A higher PRF makes the Doppler (velocity) measurement unambiguous over a larger range of speeds, but it reduces the unambiguous range because the maximum distance that can be measured without range ambiguity is c/(2×PRF). Conversely, lowering PRF expands the unambiguous range, but increases the chance of velocity aliasing, since the maximum unambiguous velocity is proportional to PRF (roughly V_unambiguous ≈ PRF × λ/4). So the main tradeoff when selecting PRF is between ambiguity in range and ambiguity in velocity. In practice, operators choose PRF to balance expected target speeds and ranges, sometimes switching PRFs or using multiple PRFs to resolve both ambiguities.