Calibration method for coupler based time domain waveform measurements

2015 ◽  
Author(s):  
Bernhard Pichler ◽  
Norbert Leder ◽  
Thomas Faseth ◽  
Holger Arthaber
Keyword(s):  
Time Domain ◽  
Calibration Method

scholarly journals Dielectric dispersion and thermodynamic behavior of stearic acid binary mixtures with alcohol as co-solvent using time domain reflectometry

2017 ◽  
Vol 07 (04) ◽  
pp. 1750027 ◽  
Author(s):  
M. Maria Sylvester ◽  
T. Ganesh ◽  
D. J. S. Anand Karunakaran ◽  
P. Senthilkumar ◽  
Praveen G. Hudge ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Stearic Acid ◽  
Time Domain ◽  
Dielectric Strength ◽  
Calibration Method ◽  
Time Domain Reflectometry ◽  
Ternary Mixtures ◽  
Relaxation Dynamics ◽  
Dielectric Parameters ◽  
Strength Formula

Dielectric permittivity and relaxation dynamics of binary and ternary mixture of stearic acid on various concentration and their thermodynamic effects are studied. The static dielectric constant ([Formula: see text]), dielectric permittivity ([Formula: see text]) and dielectric loss ([Formula: see text]) are found by bilinear calibration. The relaxation time ([Formula: see text]), dielectric strength ([Formula: see text]) and the excess permittivity ([Formula: see text]) are found. The thermodynamic parameters such as enthalpy ([Formula: see text]), entropy ([Formula: see text]) and Gibb’s free energy ([Formula: see text]) are evolved. The significant changes in dielectric parameters are due to the intramolecular and intermolecular interactions in response to the applied frequency. The permittivity spectra of stearic acid–alcohol in the frequency range of 10[Formula: see text]MHz to 30[Formula: see text]GHz have been measured using picoseconds Time Domain Reflectometry (TDR). The dielectric parameters ([Formula: see text], [Formula: see text], [Formula: see text]) are found by bilinear calibration method. Influence of temperature in intermolecular interaction and the relaxation process are also studied. The FT-IR spectral analysis reveals that the conformation of functional groups and formation for hydrogen bonding are present in both binary and ternary mixtures of stearic acid.

scholarly journals Solute Transport Measurements in Different Soil Types using Time Domain Reflectometry

2001 ◽  
Vol 32 (2) ◽  
pp. 99-114 ◽  
Author(s):  
Magnus Persson
Keyword(s):  
Solute Transport ◽  
Time Domain ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Solute Concentration ◽  
Time Domain Reflectometry ◽  
Soil Types ◽  
Undisturbed Soil ◽  
Transport Measurements ◽  
Calibration Methods

During recent years, time domain reflectometry (TDR) has proved to be a valuable tool for both water content (θ) and bulk electrical conductivity (σa) measurements. To allow resident solute concentration (Cr) measurements, a calibration procedure is necessary for the relationship between σa and Cr. Two main calibration approaches exist. Direct calibration allows for Cr measurements with varying θ, while the indirect calibration method is used for conditions with constant θ. In this paper, three methods of achieving direct calibration parameters are presented and evaluated in three different soil types. Calibrations are made in both disturbed and undisturbed soil columns as well as in the field. It was shown that there were only small differences between calibration methods in homogeneous sand. In other soils, choosing the correct calibration is important. In clay soils solute transport measurements are difficult to take under conditions with varying θ, therefore it is suggested that only the indirect calibration approach should be used. When using TDR it is important to be aware of the accuracy of the TDR system in order to interpret data correctly. Some error sources are thus also briefly discussed.

scholarly journals The Effect of Fertilization on Time Domain Reflectometry Probe Measurement Accuracy in the Field Experiment in Slovakia

2020 ◽  
Vol 23 (3) ◽  
pp. 144-149
Author(s):  
Lucia Toková ◽  
Dušan Igaz ◽  
Elena Aydin ◽  
Ján Čimo ◽  
Ján Horák
Keyword(s):  
Soil Moisture ◽  
Time Domain ◽  
Measurement Accuracy ◽  
Gravimetric Method ◽  
Calibration Method ◽  
Time Domain Reflectometry ◽  
N Fertilizer ◽  
Experimental Site ◽  
Content Determination ◽  
The Relationship

AbstractThe paper presents evaluation of the calibration method using side-by-side direct gravimetric and indirect time domain reflectometry (TDR) for soil moisture measurements to improve TDR measurement accuracy. Measurements were carried out at the experimental site Dolná Malanta (Slovakia) in 2017. Two non-fertilized treatments – without biochar (B0 + N0) and with biochar at 20 t·ha−1 (B20 + N0) – and two fertilized treatments – with biochar at 20 t·ha−1 and N fertilizer at dosages of 160 kg·ha−1 (B20 + N160) and 240 kg·ha−1 (B20 + N240) – were used in this study. The study also investigates the relationship between both used methods of soil water content determination. A strong correlation between both methods was observed. In case of (B0 + N0); (B20 + N0); (B20 + N160); and (B20 + N240), it was 0.93; 0.97; 0.97; and 0.98, respectively. However, it is assumed that the TDR probe may show errors in the results without prior calibration. It was observed that the accuracy of TDR device was lower for fertilized treatments in contrast to the gravimetric method and non-fertilized treatments. It is assumed that the higher measurement inaccuracy might be increased by salt concentration in the soil as a result of applied N fertilizer.

A time-domain calibration method for transient EM field sensors

Measurement ◽  
2021 ◽  
Vol 168 ◽  
pp. 108368
Author(s):  
Yunsheng Jiang ◽  
Zhiqian Xu ◽  
Ping Wu ◽  
Liuhong Huang ◽  
Cui Meng
Keyword(s):  
Time Domain ◽  
Calibration Method ◽  
Em Field

scholarly journals A Novel Channel Calibration Method for Bistatic ISAR Imaging System

2018 ◽  
Vol 8 (11) ◽  
pp. 2160 ◽  
Author(s):  
Lin Shi ◽  
Baofeng Guo ◽  
Juntao Ma ◽  
Chaoxuan Shang ◽  
Huiyan Zeng
Keyword(s):  
Time Domain ◽  
Pulse Compression ◽  
Imaging System ◽  
Signal To Noise Ratio ◽  
Calibration Method ◽  
Imaging Systems ◽  
Calibration Coefficient ◽  
Channel Characteristics ◽  
Isar Imaging ◽  
The Time Domain

In practical bistatic inverse synthetic aperture radar (ISAR) imaging systems, the echo signals are modulated by non-ideal amplitude and phase characteristics of the transmitting and receiving channels, which seriously distorts image quality. However, the conventional channel calibration method based on a transponder is not applicable to bistatic ISAR imaging systems, since the baseline of the system is up to hundreds of kilometers. A channel calibration method only using calibration satellite echo information is proposed for the system, with a linear frequency modulation (LFM) waveform. Firstly, echoes of the calibration satellite are collected by tracking the satellite and multi-period echoes are aligned in the time domain, according to the pulse compression result. Then, the signal to noise ratio (SNR) is improved by accumulating multi-period echoes coherently in the time domain and the calibration coefficient is constructed based on the accumulated signal. Finally, spectrum of the echo signal is multiplied with the calibration coefficient to compensate the influence of channel characteristics. The effectiveness of the proposed method is verified by the simulation experiment with real satellite echoes.

A time-domain feedback calibration method for air-coil magnetic sensor

Measurement ◽  
2019 ◽  
Vol 135 ◽  
pp. 61-70
Author(s):  
Haowen Wang ◽  
Zhihong Fu ◽  
Yao Wang ◽  
Hengming Tai ◽  
Shanqiang Qin ◽  
...  
Keyword(s):  
Time Domain ◽  
Calibration Method ◽  
Magnetic Sensor
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