pulsedecho

Pulsedecho (often written pulsed-echo) is a measurement technique used in acoustics and electromagnetics in which a transducer emits a brief pulse and then listens for echoes reflected by boundaries such as interfaces between materials or tissue layers. By measuring the time interval between emission and reception (time-of-flight) and knowing the propagation speed in the medium, the distance to the reflector can be calculated. The technique is widely used in medical ultrasonography, nondestructive testing (NDT) of materials, and radar/sonar systems with electromagnetic or acoustic waves.

In operation, a pulser excites a transducer to emit a short, broadband pulse. The receiver amplifies and processes the returning echoes. The amplitude of echoes relates to the acoustic impedance contrast at interfaces, and the timing maps to depth. In medical imaging, the echoes form A-mode or B-mode displays, yielding tomographic representations. In NDT, pulsed-echo is used for flaw detection and thickness measurements, often using the reflection from back walls or flaws.

Advantages of the pulsed-echo approach include its simplicity, speed, and ability to provide depth information with compact hardware. Limitations include resolution that is limited by pulse length, attenuation and scattering in the medium, the presence of multiple reflections and clutter, and dependence on the known propagation speed. Safety and power considerations are important in medical applications but the technique is generally noninvasive.