scholarly journals Coherent Power Measurements with a Compact Airborne Ka-Band Precipitation Radar

2018 ◽  
Vol 35 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Andrew L. Pazmany ◽  
Samuel J. Haimov
Keyword(s):  
Signal To Noise Ratio ◽  
Power Estimation ◽  
Noise Power ◽  
Signal Power ◽  
Signal To Noise ◽  
Precipitation Radar ◽  
Noise Component ◽  
Ka Band ◽  
Noise Ratio ◽  
Conventional Signal

AbstractCoherent power is an alternative to the conventional noise-subtracted power technique for measuring weather radar signal power. The inherent noise-canceling feature of coherent power eliminates the need for estimating and subtracting the noise component, which is required when performing conventional signal power estimation at low signal-to-noise ratio. The coherent power technique is particularly useful when averaging a high number of samples to improve sensitivity to weak signals. In such cases, the signal power is small compared to the noise power and the required accuracy of the estimated noise power may be difficult to achieve. This paper compares conventional signal power estimation with the coherent power measurement technique by investigating bias, standard deviation, and probability of false alarm and detection rates as a function of signal-to-noise ratio and threshold level. This comparison is performed using analytical expressions, numerical simulations, and analysis of cloud and precipitation data collected with the airborne solid-state Ka-band precipitation radar (KPR) operated by the University of Wyoming.

The Noise Analysis of Fluid Systemsin Solid-State Nanopore Sensors

2013 ◽  
Vol 419 ◽  
pp. 517-520 ◽  
Author(s):  
Song Ying ◽  
Lei Wang ◽  
Wen Yuan Zhao
Keyword(s):  
Solid State ◽  
Signal To Noise Ratio ◽  
Noise Analysis ◽  
Power Spectra ◽  
Noise Power ◽  
Label Free ◽  
Signal To Noise ◽  
Fluid Systems ◽  
Noise Ratio ◽  
Nanopore Sensors

The solid-state nanopore sensor offers a versatile platform for the rapid, label-free electrical detection and analysis of single molecules, especially on DNA sequencing. However, the overall signal-to-noise ratio (SNA) is a major challenge in sequencing applications. In our work, two different fluid systems made by metal and plexiglass have been designed to improve the signal to noise ratio of the solid-state nanopore sensor. From the measurements on the noise power spectra with a variety of conditions, it is found that plexiglass fluid system coupled with shielding box produces a good quality of electric signals on nanopore sensors.

A NEW TECHNIQUE FOR THE STUDY OF SCATTER PROPAGATION IN THE TROPOSPHERE

1957 ◽  
Vol 35 (8) ◽  
pp. 823-830 ◽  
Author(s):  
J. H. Chapman ◽  
W. J. Heikkila ◽  
J. E. Hogarth
Keyword(s):  
Power Spectrum ◽  
Communication System ◽  
Carrier Frequency ◽  
Signal To Noise Ratio ◽  
Signal Strength ◽  
Noise Power ◽  
Signal To Noise ◽  
A New Technique ◽  
Conventional Signal ◽  
Noise Power Density

The power spectrum of the fluctuations in received signal strength on a near-optical U.H.F. circuit has been measured. The sidebands associated with these fluctuations can overlap the information-carrying sidebands of a communication system. When this happens, these sidebands must be taken into account in determining the signal-to-noise ratio of the system. In other words, the fluctuations then have the characteristics of noise, and therefore they are called propagation noise in the present paper. Experiments at a carrier frequency of 500 Mc. have shown that the propagation noise power density usually varies with sideband frequency ƒ (measured from the carrier) as 1/ƒ2, for f in the range 0.1 to 10 c.p.s. Departures from this law have been observed in the regions near 0.1 c.p.s. and 10 c.p.s. The measurement of the power spectrum directly offers several advantages over the conventional signal strength recording method, and these are discussed herein.

scholarly journals Design of an Indigenised Electronic Lock-In Amplifier

2000 ◽  
Vol 23 (1) ◽  
pp. 53-60
Author(s):  
Umesh Kumar
Keyword(s):  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Broad Band ◽  
Power Line ◽  
Frequency Drift ◽  
Noise Power ◽  
Signal To Noise ◽  
Band Noise ◽  
Noise Ratio ◽  
Lock In

An indigenised lock-in amplifier is designed that enables the accurate measurement of signals contaminated by broad-band noise, power-line pick-up, frequency drift, or other sources of interference. It does this by means of an extremely narrow band detector which has the centre of its passband locked to the frequency of the signal to be measured. Large improvements in signal-to-noise ratio are achieved.

TRAVELING SIGNAL‐TO‐NOISE RATIO AND SIGNAL POWER ESTIMATES

Geophysics ◽  
1967 ◽  
Vol 32 (3) ◽  
pp. 485-493 ◽  
Author(s):  
S. M. Simpson
Keyword(s):  
Seismic Noise ◽  
Signal To Noise Ratio ◽  
Signal Strength ◽  
Noise Removal ◽  
Statistical Properties ◽  
Signal Power ◽  
Signal To Noise ◽  
Direct Estimation ◽  
Noise Ratio

Undesirable seismic noise of a nondeterministic type must be destroyed by making use of its statistical properties. Averaging of one sort or another provides methods for performing this noise removal. Our purpose here is to present a method for direct estimation of signal strength versus seismogram time, with stepout as a parameter. After describing the method and its expected behavior to some extent, we illustrate its application to a set of three noisy records.

An Improved Denoising of Electrocardiogram Signals Based on Wavelet Thresholding

2021 ◽  
Vol 51 ◽  
pp. 117-129
Author(s):  
Pinjala N. Malleswari ◽  
Ch. Hima Bindu ◽  
K. Satya Prasad
Keyword(s):  
Signal To Noise Ratio ◽  
Additive White Gaussian Noise ◽  
Ecg Signal ◽  
Noise Power ◽  
Signal To Noise ◽  
Noise Elimination ◽  
Electrocardiogram Signals ◽  
Conventional Methods ◽  
Noise Ratio ◽  
Power Line Interference

Electrocardiogram (ECG) is the most important signal in the biomedical field for the diagnosis of Cardiac Arrhythmia (CA). ECG signal often interrupted with various noises due to non-stationary nature which leads to poor diagnosis. Denoising process helps the physicians for accurate decision making in treatment. In many papers various noise elimination techniques are tried to enhance the signal quality. In this paper a novel hybrid denoising technique using EMD-DWT for the removal of various noises such as Additive White Gaussian Noise (AWGN), Baseline Wander (BW) noise, Power Line Interference (PLI) noise at various concentrations are compared to the conventional methods in terms of Root Mean Square Error (RSME), Signal to Noise Ratio (SNR), Peak Signal to Noise Ratio (PSNR), Cross-Correlation (CC) and Percent Root Square Difference (PRD). The average values of RMSE, SNR, PSNR, CC and PRD are 0.0890, 9.8821, 14.4464, 0.9872 and 10.9036 for the EMD approach, respectively, and 0.0707, 10.7181, 16.2824, 0.9874 and 10.7245 for the proposed EMD-DWT approach, respectively, by removing AWGN noise. Similarly BW noise and PLI are removed from the ECG signal by calculating the same quality metrics. The proposed methodology has lower RMSE and PRD values, higher SNR, PSNR and CC values than the conventional methods.

Increasing of the Signal-To-Noise Ratio in Precision Spectroscopy

2012 ◽  
Vol 7 (4) ◽  
pp. 19-24
Author(s):  
Evgeny Baklanov ◽  
Aleksandr Kurbatov
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Power ◽  
Doppler Broadening ◽  
Precision Spectroscopy ◽  
Signal To Noise ◽  
Narrow Resonance ◽  
Signal Noise ◽  
Radiation Noise ◽  
Noise Ratio ◽  
Multimode Regime

Is considered the possibility of increasing the signal / noise ratio in one of the main methods of laser spectroscopy without Doppler broadening – the method of saturated absorption. The colliding beam of laser radiation in a multimode regime is expected to be used. Interaction of counter propagating modes with different frequencies will increase the number of gas atoms effectively interact with the field and, consequently, the value of a narrow resonance line shape. It is shown that the photon noise, which is essentially unavoidable, signal / noise ratio can be increased in a time where – the number of modes. For other noise (power fluctuations of the radiation, noise, photo detector, etc.) the magnitude of the signal / noise ratio may increase again

scholarly journals VHF signal power suppression in stratiform and convective precipitation

2006 ◽  
Vol 24 (1) ◽  
pp. 23-35 ◽  
Author(s):  
A. J. McDonald ◽  
K. P. Monahan ◽  
D. A. Hooper ◽  
C. Gaffard
Keyword(s):  
Signal To Noise Ratio ◽  
Convective Precipitation ◽  
Small Scale ◽  
Signal Power ◽  
Signal To Noise ◽  
Bright Band ◽  
Signal Suppression ◽  
Stratiform Precipitation ◽  
Noise Ratio

Abstract. Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer. This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W). Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal suppression.

scholarly journals Position and spatial orientation of magnetic bodies from archaeological magnetic surveys

1998 ◽  
Vol 41 (3) ◽  
Author(s):  
S. Piro ◽  
S. Samir ◽  
L. Versino
Keyword(s):  
Spatial Orientation ◽  
Cross Correlation ◽  
Signal To Noise Ratio ◽  
Magnetic Data ◽  
Correlation Technique ◽  
Signal To Noise ◽  
Noise Component ◽  
Noise Ratio ◽  
Anomalous Bodies ◽  
Cross Correlation Technique

For the last twenty years magnetic surveys have frequently been applied in archaeological prospection. Among the different processing techniques that can be applied to the magnetic data, we studied the possibility for delineating the position and the spatial orientation of shallow depth magnetic anomalous bodies. The approach namely cross-correlation filter (or matched filter) has been adopted. At first, theoretical magnetic anomalies of total magnetic field, of its components and the vertical gradient of these, due to three-dimensional bodies, oriented S-N, E-W and NW-SE, were calculated. These synthetic bodies were considered a sum of many elementary prisms. Field measurements were simulated adding a noise component with different signal-to-noise ratio on the theoretical anomalies. In order to improve signal-to-noise ratio and to locate and delineate the orientation of the anomalous bodies a bidimensional cross-correlation technique was applied. Different synthetic anomalies, due to bodies with different dimensions, depths, susceptibility contrasts and geomagnetic parameters were used, as operators, to apply the cross-correlation technique. The efficiency of the method was improved using a normalised cross-correlation of the field data.

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