1. Field of the Invention
The present invention generally relates to time-domain reflectometry and, more specifically but not exclusively, to measuring an impulse response of an object, device, or system under test.
2. Description of the Related Art
This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
A time-domain (TD) reflectometer is an instrument that is designed to characterize the impulse response of an object, device, or system under test. Depending on the type of the probe waves, a TD reflectometer can be classified as an acoustic reflectometer, a radio-frequency reflectometer, an optical reflectometer, etc. Exemplary applications that rely on TD reflectometers include but are not limited to fault diagnostics for coaxial cables and optical channels, integrity tests for printed circuit boards, waveguides, and wiring systems, detection of leaks in ducts and pipelines, and medical diagnostics of bodily cavities, such as the respiratory system and the ears, nose, and throat.
For example, a typical acoustic reflectometer operates by firing a short acoustic impulse into the object under test and recording the resulting echo. More specifically, the impulse undergoes partial reflection and partial transmission at each change in the cross-sectional area along the object's bore, thereby creating a reflection wave. This wave travels back to the reflectometer where it is picked up by a microphone. A suitable algorithm is then applied to the measured reflection wave, e.g., to reconstruct the object's bore profile and/or identify possible defects, such as holes or leaks. Other types of conventional TD reflectometers operate based on a similar principle.