Signal-to-noise ratio and capture effect of microwave photonic links operating under small- and large-signal modulations in random noise

2018 ◽  
Vol 421 ◽  
pp. 30-40 ◽  
Author(s):  
S. Saied Shojaeddin ◽  
S. Esmail Hosseini ◽  
H. Abiri
Keyword(s):  
Signal To Noise Ratio ◽  
Random Noise ◽  
Capture Effect ◽  
Large Signal ◽  
Signal To Noise ◽  
Microwave Photonic ◽  
Noise Ratio ◽  
Photonic Links

Gravity meter observation of free modes excited by the August 19, 1977 Indonesia earthquake

1979 ◽  
Vol 69 (5) ◽  
pp. 1445-1454
Author(s):  
John A. Linton ◽  
D. E. Smylie ◽  
O. G. Jensen
Keyword(s):  
Signal To Noise Ratio ◽  
Quartz Fiber ◽  
Large Signal ◽  
Signal To Noise ◽  
Definitive Evidence ◽  
Long Period ◽  
Noise Ratio

abstract Free modes with signal-to-noise ratio in the range of 40 to 55 dB were observed in the record taken by a vertical broadband quartz fiber gravimeter system opeating in Montreal following the event of August 19, 1977 in Indonesia. The large signal-to-noise ratio has permitted very stable Q estimates to be made for a number of the fundamental spheroidal modes. The very long-period band shows no definitive evidence of signal other than the expected tidal lines.

Random denoising and signal nonlinearity approach by time-frequency peak filtering using weighted frequency reassignment

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. V229-V237 ◽  
Author(s):  
Hongbo Lin ◽  
Yue Li ◽  
Baojun Yang ◽  
Haitao Ma
Keyword(s):  
Weight Function ◽  
Instantaneous Frequency ◽  
Seismic Data ◽  
Signal To Noise Ratio ◽  
Random Noise ◽  
Signal To Noise ◽  
Transform Method ◽  
Time Frequency ◽  
Frequency Peak ◽  
Noise Ratio

Time-frequency peak filtering (TFPF) may efficiently suppress random noise and hence improve the signal-to-noise ratio. However, the errors are not always satisfactory when applying the TFPF to fast-varying seismic signals. We begin with an error analysis for the TFPF by using the spread factor of the phase and cumulants of noise. This analysis shows that the nonlinear signal component and non-Gaussian random noise lead to the deviation of the pseudo-Wigner-Ville distribution (PWVD) peaks from the instantaneous frequency. The deviation introduces the signal distortion and random oscillations in the result of the TFPF. We propose a weighted reassigned smoothed PWVD with less deviation than PWVD. The proposed method adopts a frequency window to smooth away the residual oscillations in the PWVD, and incorporates a weight function in the reassignment which sharpens the time-frequency distribution for reducing the deviation. Because the weight function is determined by the lateral coherence of seismic data, the smoothed PWVD is assigned to the accurate instantaneous frequency for desired signal components by weighted frequency reassignment. As a result, the TFPF based on the weighted reassigned PWVD (TFPF_WR) can be more effective in suppressing random noise and preserving signal as compared with the TFPF using the PWVD. We test the proposed method on synthetic and field seismic data, and compare it with a wavelet-transform method and [Formula: see text] prediction filter. The results show that the proposed method provides better performance over the other methods in signal preserving under low signal-to-noise ratio.

Metastable yield of argon between 23 and 37 eV by electron impact

1979 ◽  
Vol 57 (10) ◽  
pp. 1624-1633 ◽  
Author(s):  
P. Marchand ◽  
J. Cardinal
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Signal To Noise Ratio ◽  
Negative Ion ◽  
Photon Yield ◽  
Large Signal ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Yield Curves ◽  
Noise Ratio

The metastable yield of argon excited by monoenergetic electron impact has been measured between 23 and 37 eV. Thanks to a large signal-to-noise ratio, many very small structures have been detected superimposed on the metastable continuum and are attributed to Ar− negative-ion states and to highly excited states of Ar. The results are compared with broadband photon yield curves and electroionization curves.

Non-linear filtering of rare events with large signal-to-noise ratio

1987 ◽  
Vol 24 (04) ◽  
pp. 929-948
Author(s):  
A. J. Heunis
Keyword(s):  
Conditional Distribution ◽  
Signal To Noise Ratio ◽  
Sample Path ◽  
Rare Event ◽  
Dirac Measure ◽  
Linear Filtering ◽  
Large Signal ◽  
Signal To Noise ◽  
Non Linear ◽  
Noise Ratio

The theory of robust non-linear filtering in Clark (1978) and Davis (1980), (1982) is used to evaluate the limiting conditional distribution of a diffusion, given an observation of a ‘rare-event' sample-path of the diffusion, as the signal-to-noise ratio and the diffusion noise-intensity converge to infinity and zero respectively. Under mild conditions it is shown that the limiting conditional distribution is a Dirac measure concentrated at a trajectory which solves a variational problem parametrised by the sample-path of the observed signal.

ON THE DISTRIBUTION OF THE PRODUCT OF DIODE DETECTOR WAVEFORMS

1956 ◽  
Vol 34 (7) ◽  
pp. 679-691 ◽  
Author(s):  
E. L. R. Webb
Keyword(s):  
Probability Distribution ◽  
Signal To Noise Ratio ◽  
Rayleigh Distribution ◽  
Large Signal ◽  
Signal To Noise ◽  
Radio Receivers ◽  
Impulse Function ◽  
Diode Detector ◽  
Mean And Variance ◽  
Noise Ratio

The probability distribution of the product of two waveforms such as come from the diode second detectors of radio receivers is examined over the whole range of signal to noise ratios. Computed curves of probability density are given for small and moderate values of signal to noise ratio and the limiting form for large signal to noise indicated. The pure noise case is the only one immediately available in terms of tabulated functions. Compared to the Rayleigh distribution it rises much faster, reaches its maximum sooner and lower, and decays much more slowly. The very large signal to noise ratio case approaches an impulse function. Estimates of mean and variance are given.

Local symmetric distortion boosted photon up-conversion and thermometric sensitivity in lanthanum oxide nanospheres

Nanoscale ◽  
2018 ◽  
Vol 10 (19) ◽  
pp. 9245-9251 ◽  
Author(s):  
Hao Suo ◽  
Xiaoqi Zhao ◽  
Zhiyu Zhang ◽  
Rui Shi ◽  
Yanfang Wu ◽  
...  
Keyword(s):  
Lanthanum Oxide ◽  
Signal To Noise Ratio ◽  
Site Symmetry ◽  
Large Signal ◽  
Signal To Noise ◽  
Local Site ◽  
Noise Ratio

Realizing sensitive sub-tissue thermometry with a large signal-to-noise ratio via finely tailoring the local site symmetry in La2O3:Er3+/Yb3+ nanospheres.

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