The operation of aligning an ultrasonic instrument's readings to a known reference standard is called:

• A. Calibration
• B. To adjust the instrument to a reference standard
• C. To verify scanning speed
• D. To correct distance amplitude variations

Answer: (A)

Calibration is the process of aligning an ultrasonic instrument’s readings with a known reference standard so the measurements are accurate and traceable. In practice, this means using reference blocks or standards to compare the instrument’s display (for time, gain, velocity, and sensitivity) and making adjustments so the readings match the established values. This sets the instrument to true measurements and ensures consistency across tests and over time. Saying you are “adjusting the instrument to a reference standard” describes what happens during calibration, but calibration is the proper term for the overall process. Verifying scanning speed is a separate check of motion performance, and correcting distance amplitude variations relates to how signal amplitude changes with depth (a processing/compensation step) rather than the act of aligning readings to a standard.