Abstract: A method of determining a distance to a discontinuity within an object may include the steps of: a) generating a continuous, frequency modulated input signal having a predetermined frequency range and a frequency ramping speed using a signal generator and splitting the input signal into at least a test signal and a reference signal; b) generating an input sound wave based on the test signal and continuously introducing the input sound wave into the object using a transmitter and simultaneously receiving a reflected sound wave reflected by a discontinuity within the object and generating a corresponding return signal using a receiver; c) determining a frequency difference value based on a comparison of the reference signal and the return signal using a controller; and d) automatically determining a distance from the transmitter to the discontinuity within the object based on at least the frequency difference value and the frequency ramping speed.