Multi-Carrier Time Domain Reflectometry
Multi-Carrier Time Domain Reflectometry (MCTDR) is a technique for measuring the electrical characteristics of a transmission line or cable. MCTDR is a variant of multi-carrier reflectometry (MCR) in which multi-carrier signals are transmitted over the line and the reflections that return to the transmitter are measured, thus providing complete control over the spectrum of the injected signal. The reflections can be used to determine the characteristics of the transmission line, such as its impedance, attenuation, and phase shift.
In this approach to TDR measurements, the test signal is modulated as the sum of a finite number of sinusoidal oscillations and offers the advantage that the controlled spectrum of the injected signal can respond to electromagnetic compatibility (EMC) constraints. It offers the possibility to flexibly adjust the spectrum of the transmitted signal and modulate it in such a way as to allow circumvention of system-related limitations of online diagnosis by making it correspond to a specific spectral range. In this way, it is possible to avoid transmitting in a frequency band that interferes with the spectrum of the system. MCTDR is used in a variety of applications, including cable testing, fault location, and broadband transmission. It is a powerful tool for maintaining and troubleshooting transmission systems and can provide detailed information about the condition of a transmission line. MCTDR is one of the basic measurement methods in EWIS diagnostics since it can be used to detect hard faults such as short circuits and interruptions, often also intermittent defects and transient faults rather fast.