scholarly journals Review on the Millimeter-Wave Generation Techniques Based on Photon Assisted for the RoF Network System

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jiangnan Xiao ◽  
Chuang Zhao ◽  
Xingxing Feng ◽  
Xu Dong ◽  
Jiangli Zuo ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Cost ◽  
Electronic Devices ◽  
Low Frequency ◽  
Digital Signal ◽  
Development Trend ◽  
Wave Generation ◽  
Communication Link ◽  
Network System ◽  
High Frequency Microwave

With the development trend of wireless and broadband in the communication link and even the whole information industry, the demand of high-frequency microwave bandwidth has been increasing. The RoF network system solves the problem of spectrum congestion in low-frequency band by providing an effective technology for the distribution of high-frequency microwave signals over optical fiber links. However, the traditional mm-wave generation technique is limited by the bandwidth of electronic devices. It is difficult to generate high-frequency and low-phase noise mm-wave signals with pure electrical components. The mm-wave communication technology based on photon assisted can overcome the bandwidth bottleneck of electronic devices and provide the potential for developing the low-cost infrastructure demand of broadband mobile services. This paper will briefly explain the characteristics of the RoF network system and the advantages of high-frequency mm-wave. Then we, respectively, introduce the modulation schemes of RoF mm-wave generation based on photon assisted including directly modulated laser (DML), external modulation, and optical heterodyne. The review mainly focuses on a variety of different mm-wave generation technologies including multifrequency vector mm-wave. Furthermore, we list several approaches to realize the large capacity data transmission techniques and describe the digital signal processing (DSP) algorithm flow in the receiver. In the end, we summarize the RoF network system and look forward to the future.

scholarly journals A Facile, Low-Cost Plasma Etching Method for Achieving Size Controlled Non-Close-Packed Monolayer Arrays of Polystyrene Nano-Spheres

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 605 ◽  
Author(s):  
Yun Chen ◽  
Dachuang Shi ◽  
Yanhui Chen ◽  
Xun Chen ◽  
Jian Gao ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Silicon Nanowires ◽  
High Frequency ◽  
Low Cost ◽  
Etching Rate ◽  
Low Frequency ◽  
Etching Time ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
Etching System

Monolayer nano-sphere arrays attract great research interest as they can be used as templates to fabricate various nano-structures. Plasma etching, and in particular high-frequency plasma etching, is the most commonly used method to obtain non-close-packed monolayer arrays. However, the method is still limited in terms of cost and efficiency. In this study, we demonstrate that a low frequency (40 kHz) plasma etching system can be used to fabricate non-close-packed monolayer arrays of polystyrene (PS) nano-spheres with smooth surfaces and that the etching rate is nearly doubled compared to that of the high-frequency systems. The study reveals that the low-frequency plasma etching process is dominated by a thermal evaporation etching mechanism, which is different from the atom-scale dissociation mechanism that underlines the high-frequency plasma etching. It is found that the polystyrene nano-sphere size can be precisely controlled by either adjusting the etching time or power. Through introducing oxygen as the assisting gas in the low frequency plasma etching system, we achieved a coalesced polystyrene nano-sphere array and used it as a template for metal-assisted chemical etching. We demonstrate that the method can significantly improve the aspect ratio of the silicon nanowires to over 200 due to the improved flexure rigidity.

scholarly journals Modelling and Simulation using Finite Element Method of Surface Acoustic Wave Biosensor for Gas Detection Application

2021 ◽  
Vol 2071 (1) ◽  
pp. 012022
Author(s):  
A M Noor ◽  
A N Norali ◽  
Z Zakaria ◽  
M Mazalan ◽  
Y Wahab
Keyword(s):  
Numerical Simulation ◽  
Acoustic Wave ◽  
Resonance Frequency ◽  
Surface Acoustic Wave ◽  
High Frequency ◽  
Low Cost ◽  
Computational Modelling ◽  
Low Frequency ◽  
Gas Detection ◽  
Saw Sensor

Abstract A surface acoustic wave (SAW) sensor detects changes in physical properties such as mass and density on its surface. Compared to other types of sensors, SAW sensor have a good stability, high selectivity and sensitivity, fast response, and low-cost. On the other hand, to design and optimize a SAW biosensor requires a long process including time and cost using conventional methods. Therefore, numerical simulation and computational modelling are useful and efficiently conduct analysis for the SAW biosensor. In this paper, a numerical simulation technique is used to analyse the SAW device sensitivity for the application of gas detection. The SAW biosensor can detect very small mass loading by changing its sensor resonance frequency. The two-dimensional (2D) device model is based on a two-port SAW resonator with a gas sensing layer. We made two design of SAW biosensor device with frequency of 872 MHz and 1.74 GHz. A gas with vary concentration from 1 to 100 ppm were used to determine the change of the device resonance frequency. As a result, the high frequency (1.74 GHz) device, shows that the resonance frequency is shifted larger than to the low frequency (872 MHz) device. In addition, the high frequency device offers five times more sensitivity than the low frequency device. By changing the sensor design, the sensor characteristics such as sensitivity can be altered to meet certain sensing requirements. Numerical simulation provides advantages for sensor optimization and useful for nearly representing the real condition.

scholarly journals Performance Evaluation of Low Cost Analog Feedback Active Noise Cancellation System

2019 ◽  
Vol 8 (3S) ◽  
pp. 142-145
Keyword(s):  
Digital Signal Processor ◽  
Acoustic Noise ◽  
Low Cost ◽  
Low Frequency ◽  
Digital Signal ◽  
Noise Cancellation ◽  
Frequency Noise ◽  
Active Noise Cancellation ◽  
Active Noise ◽  
The Cost

Acoustic noise can be reduced by active noise cancellation (ANC) and passive noise cancellation (PNC) algorithm. The PNC can effectively attenuate the noise with high frequency, but not the noise with low frequency. ANC is one of the promising solution to reduce the low frequency noise. Commercial ANC headphones often use the digital signal processor (DSP) to perform the noise cancellation algorithm to cancel the annoying acoustic noise, but the cost is relatively high. A low-cost ANC solution is urgently needed to reduce the acoustic noise. The relationship between the frequency, distance and degree of magnitude of the noise level are also evaluated in this paper.

scholarly journals High Frequency Performance of Piezoelectric Diaphragms for Impedance-Based SHM Applications

2020 ◽  
Vol 2 (1) ◽  
pp. 16
Author(s):  
Guilherme Rezende ◽  
Fabricio Baptista
Keyword(s):  
High Frequency ◽  
Structural Damage ◽  
Low Cost ◽  
Low Frequency ◽  
Experimental Tests ◽  
Piezoelectric Transducers ◽  
Low Frequencies ◽  
High Frequencies ◽  
Electromechanical Impedance ◽  
Damage Indices

Piezoelectric transducers are used in a wide variety of applications, including damage detection in structural health monitoring (SHM) applications. Among the various methods for detecting structural damage, the electromechanical impedance (EMI) method is one of the most investigated in recent years. In this method, the transducer is typically excited with low frequency signals up to 500 kHz. However, recent studies have indicated the use of higher frequencies, usually above 1 MHz, for the detection of some types of damage and the monitoring of some structures’ characteristics that are not possible at low frequencies. Therefore, this study investigates the performance of low-cost piezoelectric diaphragms excited with high frequency signals for SHM applications based on the EMI method. Piezoelectric diaphragms have recently been reported in the literature as alternative transducers for the EMI method and, therefore, investigating the performance of these transducers at high frequencies is a relevant subject. Experimental tests were carried out with piezoelectric diaphragms attached to two aluminum bars, obtaining the impedance signatures from diaphragms excited with low and high frequency signals. The analysis was performed using the real part of the impedance signatures and two basic damage indices, one based on the Euclidean norm and the other on the correlation coefficient. The experimental results indicate that piezoelectric diaphragms are usable for the detection of structural damage at high frequencies, although the sensitivity decreases.

scholarly journals A Facile Strategy for Visualizing and Modulating Droplet-Based Microfluidics

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 291 ◽  
Author(s):  
Zehang Gao ◽  
Huo Peng ◽  
Minjie Zhu ◽  
Lei Wu ◽  
Chunping Jia ◽  
...  
Keyword(s):  
High Throughput ◽  
High Frequency ◽  
Imaging System ◽  
Low Cost ◽  
Low Frequency ◽  
Microfluidic Chips ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Additional Signal ◽  
And Control

In droplet-based microfluidics, visualizing and modulating of droplets is often prerequisite. In this paper, we report a facile strategy for visualizing and modulating high-throughput droplets in microfluidics. In the strategy, by modulating the sampling frequency of a flash light with the droplet frequency, we are able to map a real high frequency signal to a low frequency signal, which facilitates visualizing and feedback controlling. Meanwhile, because of not needing synchronization signals, the strategy can be directly implemented on any droplet-based microfluidic chips. The only cost of the strategy is an additional signal generator. Moreover, the strategy can catch droplets with frequency up to several kilohertz, which covers the range of most high-throughput droplet-based microfluidics. In this paper, the principle, setup and procedure were introduced. Finally, as a demonstration, the strategy was also implemented in a miniaturized picoinjector in order to monitor and control the injection dosage to droplets. We expect that this facile strategy supplies a low-cost yet effective imaging system that can be easily implemented in miniaturized microfluidic systems or general laboratories.

Giant Magnetoimpedance in Fe73.5Cu1Nb2V1Si13.5B9 Nanocrystalline Ribbons

2014 ◽  
Vol 809-810 ◽  
pp. 99-104 ◽  
Author(s):  
Huai Gu Hu ◽  
Yang Ming Hao ◽  
Chun Jing Gao ◽  
Yan Zhao Wu ◽  
Fei Fei Liang
Keyword(s):  
High Frequency ◽  
High Performance ◽  
Annealing Temperature ◽  
Low Cost ◽  
Low Frequency ◽  
Partial Substitution ◽  
Giant Magnetoimpedance ◽  
Giant Magnetoimpedance Effect ◽  
Average Grain Size ◽  
Optimum Annealing Temperature

In the present work, the giant magnetoimpedance effect has been found in Fe73.5Cu1Nb2V1Si13.5B9nanocrystalline ribbons. The optimum annealing temperature for obtaining largest GMI is about 550°C. Fe73.5Cu1Nb2V1Si13.5B9with average grain size of 15 nm after annealing at 550°C for 30 min presents a magnetoimpedance of-74% at 700 kHz under H=90 Oe. The MI effect at high frequency is due to the change of Z via the variation of permeability or the penetration depth under the external field. The positive magnetoimpedance ΔZ/Z is 36% and positive magnetoresistance ΔR/R is 79% at H= 10 Oe and f=5MHz. We observe a huge magnetoreactance ΔX/X of –375% at a very low frequency of 50 kHz, which is a magnetoinduction effect due to the movement of domain wall. The smaller GMI for nanocrystalline Fe73.5Cu1Nb2V1Si13.5B9ribbons annealed above 550°C is mainly connected with the decrease of permeability due to the precipitation of Fe2B phase in ribbons. Our results show that the partial substitution of expensive Nb by cheap V in FeCuNbSiB could be a successful way to prepare the GMI materials with high performance and low cost.

scholarly journals Spectral analysis of discrete signals with high frequency resolution

2019 ◽  
pp. 270-282
Author(s):  
О.В. Осипов
Keyword(s):  
Spectral Analysis ◽  
High Frequency ◽  
Time Complexity ◽  
Fourier Transforms ◽  
Electronic Devices ◽  
Digital Signal ◽  
Frequency Resolution ◽  
Frequency Responses ◽  
Discrete Signals ◽  
To Receive

Представлены алгоритмы прямого и обратного быстрого преобразований Фурье (БПФ), позволяющие обрабатывать дискретные сигналы с высоким частотным разрешением, в том числе с небольшим количеством отсчетов получать амплитудночастотные характеристики с длиной набора частот, большей, чем длина исходного дискретного сигнала. Временная сложность разработанных алгоритмов для прямого и обратного БПФ равна O(N R log2 N), где R частотное разрешение спектральной характеристики (отношение длины набора частот к длине N набора отсчетов сигнала). Разработанные методы позволят увеличить разрешающую способность отечественных систем цифровой обработки сигналов и могут быть реализованы в электронике и программном обеспечении для спектрального анализа. Algorithms of direct and inverse fast Fourier transforms are discussed. These algorithms allow one to process discrete signals with high frequency resolution, including with a small number of frequency samples, and to receive the frequency responses with a set length of frequencies greater than the length of the original discrete signal. The time complexity of the developed algorithms for the direct and inverse FFT is O(N R log2 N), where R is the frequency resolution of the spectral characteristic (the ratio of the length of a set of frequencies to the length N of a set of signal samples). The developed methods allow one to increase the resolution of systems of digital signal processing and can be implemented in electronic devices and in software for spectral analysis.

scholarly journals Study on mechanism and filter efficacy of AGO/IAGO in the frequency domain

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Changhai Lin ◽  
Zhengyu Song ◽  
Sifeng Liu ◽  
Yingjie Yang ◽  
Jeffrey Forrest
Keyword(s):  
Frequency Domain ◽  
High Frequency ◽  
Statistical Data ◽  
Low Frequency ◽  
Digital Signal ◽  
Good Effect ◽  
Data Sequence ◽  
Content Type ◽  
Noise Interference ◽  
Long Period

PurposeThe purpose of this paper is to analyze the mechanism and filter efficacy of accumulation generation operator (AGO)/inverse accumulation generation operator (IAGO) in the frequency domain.Design/methodology/approachThe AGO/IAGO in time domain will be transferred to the frequency domain by the Fourier transform. Based on the consistency of the mathematical expressions of the AGO/IAGO in the gray system and the digital filter in digital signal processing, the equivalent filter model of the AGO/IAGO is established. The unique methods in digital signal processing systems “spectrum analysis” of AGO/IAGO are carried out in the frequency domain.FindingsThrough the theoretical study and practical example, benefit of spectrum analysis is explained, and the mechanism and filter efficacy of AGO/IAGO are quantitatively analyzed. The study indicated that the AGO is particularly suitable to act on the system's behavior time series in which the long period parts is the main factor. The acted sequence has good effect of noise immunity.Practical implicationsThe AGO/IAGO has a wonderful effect on the processing of some statistical data, e.g. most of the statistical data related to economic growth, crop production, climate and atmospheric changes are mainly affected by long period factors (i.e. low-frequency data), and most of the disturbances are short-period factors (high-frequency data). After processing by the 1-AGO, its high frequency content is suppressed, and its low frequency content is amplified. In terms of information theory, this two-way effect improves the signal-to-noise ratio greatly and reduces the proportion of noise/interference in the new sequence. Based on 1-AGO acting, the information mining and extrapolation prediction will have a good effect.Originality/valueThe authors find that 1-AGO has a wonderful effect on the processing of data sequence. When the 1-AGO acts on a data sequence X, its low-pass filtering effect will benefit the information fluctuations removing and high-frequency noise/interference reduction, so the data shows a clear exponential change trends. However, it is not suitable for excessive use because its equivalent filter has poles at the non-periodic content. But, because of pol effect at zero frequency, the 1-AGO will greatly amplify the low-frequency information parts and suppress the high-frequency parts in the information at the same time.

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