scholarly journals Enhancement of signal-to-noise ratio in Brillouin optical time domain analyzers by dual-probe detection

2017 ◽  
Author(s):  
Haritz Iribas ◽  
Alayn Loayssa ◽  
Florian Sauser ◽  
Miguel Llera ◽  
Sébastien Le Floch
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Probe Detection ◽  
Noise Ratio ◽  
Optical Time ◽  
Dual Probe

scholarly journals Study on the signal-to-noise ratio of Brillouin optical-time domain analyzers

2020 ◽  
Vol 28 (14) ◽  
pp. 19864 ◽  
Author(s):  
Sheng Wang ◽  
Zhisheng Yang ◽  
Marcelo A. Soto ◽  
Luc Thévenaz
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Optical Time

scholarly journals Applications of Continuous Wave Free Precession Sequences in Low-Field, Time-Domain NMR

2019 ◽  
Vol 9 (7) ◽  
pp. 1312 ◽  
Author(s):  
Tiago Bueno Moraes ◽  
Tatiana Monaretto ◽  
Luiz Colnago
Keyword(s):  
Time Domain ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Flip Angle ◽  
Time Interval ◽  
Single Shot ◽  
Free Precession ◽  
Signal To Noise ◽  
Low Field ◽  
Noise Ratio

This review discusses the theory and applications of the Continuous Wave Free Precession (CWFP) sequence in low-field, time-domain nuclear magnetic resonance (TD-NMR). CWFP is a special case of the Steady State Free Precession (SSFP) regime that is obtained when a train of radiofrequency pulses, separated by a time interval Tp shorter than the effective transverse relaxation time (T2*), is applied to a sample. Unlike regular pulsed experiments, in the CWFP regime, the amplitude is not dependent on T1. Therefore, Tp should be as short as possible (limited by hardware). For Tp < 0.5 ms, thousands of scans can be performed per second, and the signal to noise ratio can be enhanced by more than one order of magnitude. The amplitude of the CWFP signal is dependent on T1/T2; therefore, it can be used in quantitative analyses for samples with a similar relaxation ratio. The time constant to reach the CWFP regime (T*) is also dependent on relaxation times and flip angle (θ). Therefore, T* has been used as a single shot experiment to measure T1 using a low flip angle (5°) or T2, using θ = 180°. For measuring T1 and T2 simultaneously in a single experiment, it is necessary to use θ = 90°, the values of T* and M0, and the magnitude of CWFP signal |Mss|. Therefore, CWFP is an important sequence for TD-NMR, being an alternative to the Carr-Purcell-Meiboom-Gill sequence, which depends only on T2. The use of CWFP for the improvement of the signal to noise ratio in quantitative and qualitative analyses and in relaxation measurements are presented and discussed.

scholarly journals Improving the Signal-to-Noise Ratio of Time Domain Fiber Bragg Grating Sensor Based on Hybrid Simplex and Golay Coding Technique

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 167089-167098
Author(s):  
Mohamed M. Elgaud ◽  
Mohd Saiful Dzulkefly Zan ◽  
Abdulfatah Abushagur Ghaith ◽  
Ahmad Ashrif A. Bakar ◽  
Norhana Arsad ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Fiber Bragg Grating Sensor ◽  
Bragg Grating ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Bragg Grating Sensor
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