Conversion Loss of Diode Mixers Having Image-Frequency Impedance

1945 ◽  
Vol 33 (9) ◽  
pp. 603-609 ◽  
Author(s):  
E.W. Herold ◽  
R.R. Bush ◽  
W.R. Ferris
1970 ◽  
Vol 6 (11) ◽  
pp. 321-322 ◽  
Author(s):  
P. Albrecht ◽  
M. Bechteler

2018 ◽  
Author(s):  
Mathieu Schaer ◽  
Christophe Praz ◽  
Alexis Berne

Abstract. A new method to automatically discriminate between hydrometeors and blowing snow particles on Multi-Angle Snowflake Camera (MASC) images is introduced. The method uses four selected descriptors related to the image frequency, the number of particles detected per image as well as their size and geometry to classify each individual image. The classification task is achieved with a two components Gaussian Mixture Model fitted on a subset of representative images of each class from field campaigns in Antarctica and Davos, Switzerland. The performance is evaluated by labelling the subset of images on which the model was fitted. An overall accuracy and Cohen's Kappa score of 99.4 and 98.8 %, respectively, is achieved. In a second step, the probabilistic information is used to flag images composed of a mix of blowing snow particles and hydrometeors, which turns out to occur frequently. The percentage of images belonging to each class from an entire austral summer in Antartica and during a winter in Davos, respectively, are presented. The capability to distinguish precipitation, blowing snow and a mix of those in MASC images is highly relevant to disentangle the complex interactions between wind, snowflakes and snowpack close to the surface.


2018 ◽  
Vol 12 (2) ◽  
pp. 147-158 ◽  
Author(s):  
Wei Zhou ◽  
Liqun Gan ◽  
Hong Xiao ◽  
Yi Zhang ◽  
Haitao Xu ◽  
...  

This paper presents an improved frequency estimation algorithm based on the interpolated discrete Fourier transform. High-accurate frequency estimation can be achieved by taking the geometric mean of two independent estimates, which are derived from the real parts of the two largest spectral bins and the imaginary parts, respectively. In situations where only a small number of sine wave cycles are observed, the ability of the algorithm to cancel interference from image frequency components results in improvements in accuracy. The residual errors of the proposed algorithm have been theoretically analyzed with maximum side-lobe decaying windows, since the windows have simple and uniform analytical expression of interpolation algorithm. The performance of the proposed algorithm was investigated using both Hanning and three-term maximum side-lobe decaying windows. A comparative analysis of systematic errors and noise sensitivity was performed between the new algorithm and traditional algorithms. Both the root mean squared error and the probability density of the errors were investigated under noisy conditions. Simulation results demonstrated that the new algorithm is not only highly resistant to interference from image components but is also resistant to the effects of random noise. The results presented in the paper are useful for identifying the best choice of algorithm in practical engineering applications.


2019 ◽  
Vol 40 (2) ◽  
pp. 325-328 ◽  
Author(s):  
Mengchuan Tian ◽  
Xuefei Li ◽  
Qingguo Gao ◽  
Xiong Xiong ◽  
Zhenfeng Zhang ◽  
...  

Author(s):  
Konstantin Korotkov ◽  
Akim Babenko ◽  
Daniil Frolov ◽  
Dmitriy Nereutskiy ◽  
Anton Levchenko
Keyword(s):  

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