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The spectrum of the image reflects the distribution of image energy in the frequency domain. The ratio of the high and low frequency components of the spectrum reflects the distribution of edge information and smooth information in the image. Through statistical analysis of the spectral distribution of dear and blurred images, this paper proposes an image clarity and fuzzy discrimination method based on sub-band spectral information. First, the spectrum energy outside the frequency radius is calculated, and the characteristic curve of the residual energy of the spectrum is obtained. Secondly, according to the residual energy curve, the normalized fuzzy judgment parameters are obtained. When the fuzzy parameter is less than a certain threshold, the image is judged to be a blurred image. The experimental results show that the parameter proposed in this paper can quantitatively measure the degree of image blur, and has the advantages of fast and simple judgment process and high classification discrimination. [ABSTRACT FROM AUTHOR]

To overcome currently existing problems of poor scalability and high price of virtual oscilloscopes, a virtual oscilloscope is developed by using compressed sensing signal processing technology and STM32, field programmable gate array (FPGA) and other modules combined with personal computers (PCs). It has 50 MB bandwidth and 100 MS/s sampling frequency. It is connected to a PC via a high-speed universal serial bus ( USB ) interface. Besides the waveform display and measurement functions of traditional oscilloscopes, it also has flexible and programmable software extensions, such as the signal generator, the spectrum analysis, and the amplitude-frequency measurement. Compared with the existing virtual oscilloscope, the developed virtual oscilloscope has many advantages, such as various functions, low cost, high expandability and easy portability. [ABSTRACT FROM AUTHOR]

This work provides a research-oriented comprehensive organic chemistry teaching experiment converted from a mature scientific research achievement in desymmetrization of meso and other prochiral compounds. The naturally-occurring cinchona alkaloids quinine mediated organocatalytic enantioselective methanolysis of meso-cyclic anhydride was utilizedas a tool for preparation of the corresponding chiral hemiester, which is the key intermediate of ( + )-biotin, and the products were characterized by IR , NMR spectroscopy and specific rotation. Finally, the method of crystallization resolution of diastereoisomers was usedto recycle organocatalyst quinine. Through the experiment students not only consolidate the basic principles of asymmetric synthesis and chemical resolution, but also have abetter understanding of instrument working principle and improve the actual operation skills of the rotary evaporator, thin layer chromatography, infrared spectrometer and nuclear magnetic resonance instrument. In a word, the systematic experimental procedure can help students to consolidate the comprehensive ability including the relevant synthetic strategy of organic chemistry, synthetic chemistry experiment skill and spectra analysis. Moreover, the recovery process of organocatalyst creates a favorable teaching environment to set up the concept of “green chemistry” for undergraduates. [ABSTRACT FROM AUTHOR]

Based on the Mandarin pronunciation recognition technology, by the frequency selected from Mandarin speech input cavity resonance curve defined by the pickup, the Chinese word, vowel and consonant Pinyin word sequence can be identified. Combination of Chinese speech consonants, vowels and tones forms Chinese Pinyin sentence sequence. By the syllable by syllable analysis method, the frequency domain analysis technique of amplitude frequency does not need to learn or train for a particular persons voice, words and sentences. The adaptive DFT ( Discrete Fourier Transform) spectral analysis algorithm only occupies a very small amount of calculation. The method can determine the four tones of Mandarin, have fast response speed, small storage space, and can easilybe embedded to other devices. [ABSTRACT FROM AUTHOR]

An instrumental analysis experiment was introduced : simultaneous identification and quantitative determination of components in Paracetamol, Aminophenazone, Caffeine and Chlorphenamine Maleate Tablets using 1HNuclear Magnetic Resonance Spectroscopy. This paper introduces the purpose, procedure and effect of this experiment. Qualitative and quantitative analyses are based on resonance characteristics of the functional groups and the integral ratio of selected signals belonging to different compounds, respectively. This method covers the main points of nuclear magnetic resonance spectroscopy, which will help students learn this part better. [ABSTRACT FROM AUTHOR]

This paper introduces Fourier transformation, and its important role of fast Fourier transform (FFT) in the analysis of signal spectrum. According to the important properties of polymer materials--viscoelasticity, the paper deals with the spectral analysis by using fast Fourier transform and computer software MATLAB. It explores possibility of spectrum analysis of the methods using polymer materials by using fast Fourier transform, at least the possibilities in the experimental polymer material impact on the spectrum. From these results, it maybe extend the application of Fourier transform. [ABSTRACT FROM AUTHOR]

There is need to develop a portable experimental platform for digital signal processing. In order to solve this problem, using DSP ( Digital Signal Processor) + FPGA ( Field Programmable Gate Array) as the hardware platform, a low-cost, portable digital signal processing experimental system is designed. Digital signal processor TMS320VC5509A is used as data processing core. FPGA is applied to control USB, ADC, DAC and the other peripheral devices, so that the experimental system can communicate with the PC and complete conversion between analog and digital signals. Besides, the platform can also implement the classical digital signal processing algorithms, such as spectral analysis, digital filter design, etc. Hardware debug shows that the platform can generate the basic signal for digital signal processing, and it can implement the basic experimental content for DSP course. The experimental platform can greatly enhance intuitive of the digital signal processing course. [ABSTRACT FROM AUTHOR]