Chirplet Time Domain Reflectometry (TDR)

Publish Date: Sep 28, 2012 | 0 Ratings | 0.00 out of 5 | Submit your review


This example shows the application of the Time Frequency Analysis VIs in Time Domain Reflectometry (TDR). A TDR is an instrument that characterizes and locates faults in cables. You can transmit a chirplet along a cable and receive the reflected signal. The reflected signal also is a chirplet but has different time center, amplitude, and others. You can characterize and locate faults in the cable based on the difference between the transmitted chirplet and the reflected chirplet. A TDR signal contains both the transmitted and the reflected chirplets. One of the challenges in the applications of TDR is how to separate and extract parameters of the transmitted and the reflected chirplets. This example simulates the TDR signal from a cable and uses the TFA Adaptive Transform VI to extract the parameters of these two chirplets. This program is a shipping example VI included with the Advanced Signal Processing Toolkit for NI LabVIEW.

This software is written in LabVIEW, a graphical programming language designed for scientists and engineers. For more information about LabVIEW, visit

Advanced Signal Processing Toolkit Example Programs
The National Instruments Advanced Signal Processing Toolkit is a suite of high level VIs, libraries, software tools, example programs, and utilities for time-frequency analysis and digital filter design. With this toolkit, you can experiment and develop with modern analysis techniques that include wavelets, super resolution (model-based) spectral analysis, and joint time-frequency analysis (JTFA). Also included is the National Instruments LabVIEW Digital Filter Design Toolkit, which allows you to interactively design and characterize finite impulse response (FIR) and infinite impulse response (IIR) filters.

More information on National Instruments signal processing can be found at the Signal Processing Resource Center.

1. Front Panel

This is a picture of the VI's front panel.

To view the block diagram and additional documentation, install the Advanced Signal Processing Toolkit and complete the following steps:

  1. Launch LabVIEW.
  2. In LabVIEW, select Help»Find Examples to launch the NI Example Finder.
  3. In NI Example Finder, browse to Toolkits and Modules»Time Frequency Analysis»Applications»Chirplet and open this example VI.
  4. Display the block diagram of this VI to obtain more information.

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