Jump to content

Amplitude domain reflectometry

Add links
From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Kkmurray (talk | contribs) at 22:25, 31 August 2015 (Added {{one source}} tag to article (TW)). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Many of the soil moisture measuring instruments are based on the principle of Amplitude Domain Reflectometry (ADR). This method measures the electrical impedance. Electromagnetic waves traveling along Transmission Line (TL) enter in soil medium whose impedance is different from TL a part of the energy is reflected back to transmitter. The reflected wave interferes with incident wave and produces a standing wave along the TL, this changes the amplitude of wave along the TL. The impedance can be measured from difference in amplitude. The impedance has two components: electrical conductivity and dielectric constant. The effect of conductivity can be minimized by selecting an appropriate frequency.

References

Robinson, D. A., C. S. Campbell, J. W. Hopmans, B. K. Hornbuckle, S. B. Jones, R. Knight, F. Ogden, J. Selker and O. Wendroth (2008), Soil moisture measurement for ecological and hydrological watershed-scale observatories: A review, Vadose Zone Journal, 7(1), 358-389.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Amplitude_domain_reflectometry&oldid=678833853"