Frequency-Swept Electronic Driver for Wideband Applications of Air-Coupled Ultrasound Transducers

The ultrasound is a common way to measure the distance or detect an object. This is usually carried out by measuring the time-of-flight of the received echoes reflected by the objects, which is a parameter easily obtained from the signal and that only provides the spatial location. In the present paper, it is presented an electronic signal generator to drive air-coupled ultrasound transducers in a wideband regime. This design is planned to be used as a new application of these sensors, normally used for distance measuring, which is to characterize materials by using the complete signal of the echo to extract more useful information. The design was made with simple materials, but mainly based on a programmed microcontroller capable of making a specified frequency sweep that allows us to create a moderate-power tone burst with the use of a switched amplifier at the output. The tone burst produced by the microcontroller varies the pulse-width in time, obtaining the controllable frequency sweep that has a wide excitation spectrum.