Short pulse ultrasonic generation with a bar type magnetostrictive transducer with saturated magnetization

The way for shooting a short ultrasonic pulse by a magnetostrictive bar type transducer is investigated. The method is as follows, 1. Make magnetization of the transducer to be saturated by a bias coil. 2. Induce a short pulse voltage or current to a driving coil. The half breadth of the signal is much shorter than the fundamental resonant period of the transducer. In a result, the short pulse ultrasonic waves are generated and launched. The reason of the phenomena is, we think, that the both ends of the bar transducer are not saturated, because the demagnetization exists on the sides.