Selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers
Li Ming-Liang, Deng Ming-Xi†, , Gao Guang-Jian
       

Ultrasonic signals at f = 1.85 MHz: (a) time–domain signal at Δz = 280 mm, (b) STFT spectrogram, (c) slice of STFT spectrogram at f = 1.85 MHz.