Based on the propagation characteristics of ultrasonic waves in solid materials，a laboratory-scale acoustic flaw detection system was developed，comprising an ultrasonic transducer，signal generator，

oscilloscope，test specimens，and associated connecting cables．The ultrasonic transducer is activated by specific frequency pulse waves through the signal generator，waveform acquisition and analysis were performed using the oscilloscope，enabling precise measurements of ultrasonic propagation velocities in solids．Using a 2．5 MHz transducer，the measured velocities were determined as 6，195．6 m/s in the magnet，6，427．4 m/s in the aluminum block，5，725．4 m/s in glass，and 2，619．8 m/s in acrylic．Furthermore，this apparatus demonstrated extended functionality in defect localization within aluminum components and three-dimensional structural reconstruction of a glass penholder through translational scanning measurements． To optimize measurement accuracy，the influence of input pulse frequency variations was systematically investigated．experimental results revealed enhanced measurement precision when the excitation pulse frequency was maintained at 2-4 times the transducer＇s inherent resonant frequency．This frequency-dependent behavior underscores the critical role of spectral matching between the driving signal and transducer characteristics for improved system performance．