scholarly journals UNetGAN: A Robust Speech Enhancement Approach in Time Domain for Extremely Low Signal-to-Noise Ratio Condition

2019 ◽  
Author(s):  
Xiang Hao ◽  
Xiangdong Su ◽  
Zhiyu Wang ◽  
Hui Zhang ◽  
A Batushiren
Keyword(s):  
Speech Enhancement ◽  
Time Domain ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Ratio Condition ◽  
Noise Ratio

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.

Measurement of Signal-to-Noise Ratio and Signal-to-Noise and Distortion Ratio Using Histogram Test in Time Domain Analysis

2021 ◽  
pp. 403-410
Author(s):  
Manish Jain ◽  
Prakash Chandra Sharma ◽  
Pradeep Kumar Tiwari ◽  
Rohit Kumar Gupta
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Signal To Noise ◽  
Noise Ratio
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