In contact testing, what may occur if the UT instrument is set with an excessively high pulse repetition rate?

• A. Ghost or Phantom Indications
• B. Increased Amplitude
• C. No Echoes Detected
• D. Constant Baseline Drift

Answer: (A)

Pulse repetition rate is how often you send pulses and how long the receiver waits before the next pulse. If this rate is set too high, echoes from an earlier pulse can still be present when a new pulse is fired. That time-domain overlap makes signals from different pulses appear together, producing false reflections that look like real features. These ghost or phantom indications are a key risk of an excessively high PRF in contact testing. The other effects listed aren’t directly caused by PRF: amplitude changes come from gain, coupling, or reflector strength; no echoes or baseline drift usually point to coupling issues, detector setup, or electronics, not simply the pulse rate.