An instrument display in which the horizontal baseline represents elapsed time and the vertical deflection represents signal amplitude is called:

An instrument display in which the horizontal baseline represents elapsed time and the vertical deflection represents signal amplitude is called:

• A. A-scan
• B. B-scan
• C. C-scan
• D. M-scan

Answer: (A)

This item is about identifying the one-dimensional amplitude-versus-time display used in ultrasonic testing. In this display, the horizontal axis represents the elapsed time from emission to reception, and the vertical axis shows the echo amplitude. Strong reflections appear as spikes whose timing corresponds to the distance to reflectors because the travel time is related to how far the sound wave has traveled. The depth to a reflector is found from the travel time using the speed of sound in the material: depth equals half the travel time multiplied by the sound speed (since the pulse travels to the reflector and back). For example, if the round-trip time is 5 microseconds and the material's sound speed is 5.94 mm per microsecond, the reflector is about 14.85 mm deep. This type of display is distinct from other scan types that produce two-dimensional images or time-motion plots. A B-scan forms a 2D cross-sectional image by combining traces across a scan line, a C-scan provides a plan-view map, and an M-scan shows how a single A-scan trace changes over time as the probe or setup moves. The described horizontal-time, vertical-amplitude trace is the A-scan.

This item is about identifying the one-dimensional amplitude-versus-time display used in ultrasonic testing. In this display, the horizontal axis represents the elapsed time from emission to reception, and the vertical axis shows the echo amplitude. Strong reflections appear as spikes whose timing corresponds to the distance to reflectors because the travel time is related to how far the sound wave has traveled.

The depth to a reflector is found from the travel time using the speed of sound in the material: depth equals half the travel time multiplied by the sound speed (since the pulse travels to the reflector and back). For example, if the round-trip time is 5 microseconds and the material's sound speed is 5.94 mm per microsecond, the reflector is about 14.85 mm deep.

This type of display is distinct from other scan types that produce two-dimensional images or time-motion plots. A B-scan forms a 2D cross-sectional image by combining traces across a scan line, a C-scan provides a plan-view map, and an M-scan shows how a single A-scan trace changes over time as the probe or setup moves. The described horizontal-time, vertical-amplitude trace is the A-scan.