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FMCW Sensors for Detecting Hidden Objects
Published in Boris Y. Kapilevich, Stuart W. Harmer, Nicholas J. Bowring, Non-Imaging Microwave and Millimetre-Wave Sensors for Concealed Object Detection, 2017
Boris Y. Kapilevich, Stuart W. Harmer, Nicholas J. Bowring
The minimum detectable signal (MDS) of the receiver is the lowest power level at which it can detect an incoming signal in a presence of noise. This is an important parameter required for evaluation of the dynamic range of the receiver. So that
Liquid crystal light valves as optically addressed liquid crystal spatial light modulators: optical wave mixing and sensing applications
Published in Liquid Crystals Reviews, 2018
S. Residori, U. Bortolozzo, J. P. Huignard
Theoretically, let us assume that there are N photons in each of the input beams. After the interaction, the number of photons will be increased on one of the beams and symmetrically decreased in the other one of a quantity . The total output signal is proportional to the linear part of the gain curve , where χ represents the slope of the gain curve as a function of the frequency detuning. The minimum detectable signal is determined by the intensity of the photon shot noise. Since we are using coherent states, the uncertainty of the signal, for small Doppler shift is . The signal to noise ratio is, therefore, . By taking into account the quantum efficiency η of the detector we obtain the expression for the signal to noise ratio .
Detection of RDX traces at the surface with sonic aerosol flow desorption
Published in Aerosol Science and Technology, 2018
Viktor V. Pervukhin, Yuri N. Kolomiets
The relationship between the amplitude of the RDX peak and the amount of the sample deposited on the concentrator (Figure 3) is linear. To determine the minimum detectable signal, ULOD (i.e. the sensitivity of the GC), we use the value Unois and assume that the signal is detected, if signal to noise (S/N) ratio is three: ULOD = 3×Unois = 0.087 V.