电气工程代写|通讯系统作业代写communication system代考|ELN234

statistics-lab™ 为您的留学生涯保驾护航 在代写通讯系统communication system方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写通讯系统communication system方面经验极为丰富，各种代写通讯系统communication system相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• Advanced Probability Theory 高等楖率论
• Advanced Mathematical Statistics 高等数理统计学
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

电气工程代写|通讯系统作业代写communication system代考|Over-rotation during electro-optical sampling

It is noted in Formula (7) that the modulation is bounded by $-1$ and 1 for phase differences of $-\pi / 2$ and $\pi / 2$, respectively. If the phase difference exceeds $\pi / 2$, the modulation decreases instead of increases since it has a sinusoidal behavior. This problem related to electro-optical detection is called over-rotation. Since a large phase difference is usually caused by a high electric field, EOS can only be used for detecting weak THz fields if over-rotation is to be avoided.

There are of course ways to work around the over-rotation problem and detect high THz fields. According to Formula (6), a smaller phase difference can be obtained by using a thinner detection crystal or having a lower electro-optical coefficient. In the first case, it should be known that a THz pulse incident on a crystal always generates reflections, which can also be detected. The thinner the crystal, the closer the reflection is temporally to the main pulse, and therefore, the more it is necessary to reduce the time window of the measurement in order to avoid measuring the reflection. However, a short time window also means a low frequency resolution, which is generally undesirable. In addition, a thinner crystal also means a shorter interaction length of the waves in the crystal, which results in a decrease in the Signalto-Noise Ratio (SNR). In the second case, it is actually possible to use a crystal with a lower electro-optical coefficient than $\mathrm{ZnTe}$, for example, gallium phosphide (GaP), and with which it is much more difficult to obtain over-rotation. On the other hand, the measured signal-to-noise ratio is then lower.

The most common solution to over-rotation is the addition of silicon waffles in the mounting just before the detection crystal (see Fig. 3). Part of the THz pulse (30\%) is reflected on each silicon waffle. The goal is to add enough silicon waffles so that the THz field reaching the crystal is both under the over-rotation limit and in the linear regime $(\sin (\Delta \varphi)=\Delta \varphi)$. However, adding several silicon waffles may cause some deformations in the detected THz field. In addition, a high THz field can induce nonlinear effects in silicon and the reflection on each waffle is then lower than $30 \%$. Also, multiple $\mathrm{THz}$ reflections on the silicon waffles are always at the tail of the main pulse in a measurement, which limits the time acquisition length and therefore the frequency resolution.

Of course, if silicon waffles are added to the assembly, this must be taken into account when calculating the THz field. By also adding the reflection losses on the detection crystal, we obtain:
$$E_{\mathrm{THz}}=\frac{d M}{2 \pi n_0^3 L r_{41} \Gamma 0.7^N}$$
where $\Gamma$ is the transmission coefficient through the detection crystal and $N$ is the number of waffles of Si. Each waffle transmits $70 \%$ of the THz wave.

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Plasma in Air

There are two methods of plasma THz detection in air called THz-ABCD. The first is $\mathrm{THz}$ Air Breakdown Coherent Detection. The principle is very similar to $\mathrm{THz}$ generation by plasma in the air: A femtosecond laser is focused in the air, which generates a plasma whose charges are accelerated. If one sends a $\mathrm{THz}$ pulse to be detected on the plasma at the same time (or almost) as the laser pulse, there will be generation of the second harmonic of the laser beam. By detecting this second harmonic using a photomultiplier tube, the THz field can be deduced:
$$I_{2 \omega} \propto\left|E_{2 \omega}\right|^2 \propto\left(W^{(3)} E_\omega E_\omega\right)^2 E_{\mathrm{THz}}^2$$
where $I_{2 \omega}$ is the intensity of the second harmonic of the laser, $W^{(3)}$ is the 3rd order nonlinear coefficient of the plasma, $E_\omega$ is the laser electric field, $E_{2 \omega}$ is the electric field of the second harmonic of the laser, and $E_{\mathrm{THz}}$ is the electric field THz.

Unfortunately, since we only measure the intensity of the second harmonic, we cannot measure the electric field coherently. To achieve consistent detection, a very intense laser intensity must be used. At high pump intensity, the white light generated by the plasma contains a non-negligible second harmonic component that must be considered in the calculation [31]:
$$I_{2 \omega} \propto\left|E_{2 \omega}\right|^2 \propto\left(W^{(3)} E_\omega E_\omega\right)^2 E_{\mathrm{THz}}^2+2\left(W^{(3)} E_\omega E_\omega\right) E_{\mathrm{THz}} E_{\mathrm{SH}}^{2 \omega}+\left(E_{\mathrm{SH}}^{2 \omega}\right)^2$$
where $E_{\mathrm{SH}}^{2 \omega}$ is the electric field of the second harmonic from the plasma.
If the field of the second harmonic coming from the plasma is high enough, the first term of Formula (11) becomes negligible and the intensity detected by the photomultiplier tube is then proportional to the electric field $\mathrm{THz}$, making the detection method consistent. Of course, a drawback is that it is not possible to detect a $\mathrm{THz}$ field that is too large (or it is necessary to compensate with the intensity of the pump laser) since the first term of Formula (11) would then no longer be negligible. The second THz method is THz Air Bias Coherent Detection (THz-ABCD). This method requires a lower laser intensity, but an $\mathrm{AC}$ electric field must be applied close to the focal point.

电气工程代写|通讯系统作业代写communication system代考|Over-rotation during electro-optical sampling

$$E_{\mathrm{THz}}=\frac{d M}{2 \pi n_0^3 L r_{41} \Gamma 0.7^N}$$

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Plasma in Air

$$I_{2 \omega} \propto\left|E_{2 \omega}\right|^2 \propto\left(W^{(3)} E_\omega E_\omega\right)^2 E_{\mathrm{THz}}^2$$

$$I_{2 \omega} \propto\left|E_{2 \omega}\right|^2 \propto\left(W^{(3)} E_\omega E_\omega\right)^2 E_{\mathrm{THz}}^2+2\left(W^{(3)} E_\omega E_\omega\right) E_{\mathrm{THz}} E_{\mathrm{SH}}^{2 \omega}+\left(E_{\mathrm{SH}}^{2 \omega}\right)^2$$

广义线性模型代考

statistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

电气工程代写|通讯系统作业代写communication system代考|ECE3614

statistics-lab™ 为您的留学生涯保驾护航 在代写通讯系统communication system方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写通讯系统communication system方面经验极为丰富，各种代写通讯系统communication system相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• Advanced Probability Theory 高等楖率论
• Advanced Mathematical Statistics 高等数理统计学
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Photoconductive Antennas

The principle of detection by photoconductive antennas is similar to that of generation. As for the generation, a laser pulse (visible or infrared) is sent to the semiconductor component of the antenna, between the two electrodes, in order to reduce its resistance. On the other hand, unlike the generation, no potential difference is imposed between the electrodes; here, it is the incident THz field which acts on the displacement of the photoporters. A current can then pass between the two electrodes. By measuring this current, we can determine the $\mathrm{THz}$ field using the expression that binds the two, i.e., [25]:
$$I(t)=\int_{-\infty}^t \epsilon\left(t-t^{\prime}\right) E_{\mathrm{THz}} \mathrm{d} t^{\prime}$$
where $I(t)$ is the current induced by the $\mathrm{THz}$ field, $\epsilon$ is the surface conductivity of the semiconductor, and $E_{\mathrm{TH} z}$ is the electric field $\mathrm{THz}$.

Photoconductive antennas are mainly used for the detection of low and medium high $\mathrm{THz}$ electric fields. Indeed, a strong $\mathrm{THz}$ electric field could induce nonlinear effects in the semiconductor and the above formula would then no longer be valid [13].

Generally, the detection of terahertz radiation using photoconductive antennas is quite similar to its emission: This time it is the incident terahertz electric field which induces a voltage between two arms of the antenna connected by a transmission line to a current amplifier. Indeed, a laser pulse excites charge carriers beyond the bandgap of the semiconductor photoswitch. The charge carriers are accelerated by the external terahertz field to be detected, such that, still in the context of the Drude model. The current measured by an ammeter is then the convolution of the sampling field $E_S^{(d)}$ and the flow of charge carriers in the detector antenna:
$$I^{(d)}(t)=E_S^{(d)} *\left(e n^{(d)}(t) V(t)\right)$$

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Electro-Optical Sampling

Electro-optical sampling (EOS) is a technique based on the Pockels effect, which is the inverse of optical rectification. The Pockels effect is the induction of birefringence in a nonlinear crystal by a DC wave. In the case of THz detection by electro-optical sampling, it will be approximated that the $\mathrm{THz}$ wave is a DC wave since its frequency is much smaller than the visible or near infrared wave used as a probe. The THz wave is therefore sent on a non-centrosymmetric crystal, which induces a change in the polarization ellipsoid in the crystal, and therefore in the ellipsoid of the refractive indices of the crystal. For example, for a ZnTe crystal (or any other crystal with a blende-like structure), the ellipsoid of indices becomes [28]:
$$\frac{\alpha^2+\beta^2+\gamma^2}{n_0^2}+2 r_{41} E_\alpha \beta \gamma+2 r_{41} E_\beta \alpha \gamma+2 r_{41} E_\gamma \alpha \beta=1$$
where $\alpha, \beta, \gamma$ are the spatial coordinates corresponding to the axes of the crystal, $n_0$ is the refractive index of the crystal without exposure $\mathrm{THz}, r_{41}$ is the electro-optical coefficient of the crystal and $E_\alpha, E_\beta, E_\gamma$, are the electric fields $\mathrm{THz}$ applied along the axes $\alpha, \beta, \gamma$.

The THz wave thus induces a birefringence in the nonlinear crystal. This birefringence is probed by a second beam sent on the crystal. This beam, visible, or near infrared undergoes a change in polarization during its passage in the birefringent crystal since the optical component parallel to the slow axis of the crystal undergoes a phase delay with respect to the optical component parallel to the fast axis of the crystal [28]:
$$\Delta \varphi=\frac{2 \pi L}{d} \Delta n$$
where $\Delta \varphi$ is the induced phase difference, $L$ is the thickness of the crystal $d$ is the central wavelength of the probe pulse and $\Delta n$ is the difference between the refractive indices of the slow and fast axes of the crystal. For a beam orthogonal to an oriented ZnTe crystal (110) with an electric field oriented along the axis $(-110)$ of the crystal, i.e., the optimal position [29]:
$$\Delta \varphi=\frac{2 \pi n_0^3 L r_{41} E_{\mathrm{THz}}}{d}$$

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Photoconductive Antennas

$$I(t)=\int_{-\infty}^t \epsilon\left(t-t^{\prime}\right) E_{\mathrm{THz}} \mathrm{d} t^{\prime}$$

$$I^{(d)}(t)=E_S^{(d)} *\left(e n^{(d)}(t) V(t)\right)$$

电气工程代写|通讯系统作业代写communication system代考|THz Detection by Electro-Optical Sampling

$$\frac{\alpha^2+\beta^2+\gamma^2}{n_0^2}+2 r_{41} E_\alpha \beta \gamma+2 r_{41} E_\beta \alpha \gamma+2 r_{41} E_\gamma \alpha \beta=1$$

$$\Delta \varphi=\frac{2 \pi L}{d} \Delta n$$

$$\Delta \varphi=\frac{2 \pi n_0^3 L r_{41} E_{\mathrm{THz}}}{d}$$

广义线性模型代考

statistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

电气工程代写|通讯系统作业代写communication system代考|ENG307

statistics-lab™ 为您的留学生涯保驾护航 在代写通讯系统communication system方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写通讯系统communication system方面经验极为丰富，各种代写通讯系统communication system相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• Advanced Probability Theory 高等楖率论
• Advanced Mathematical Statistics 高等数理统计学
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

电气工程代写|通讯系统作业代写communication system代考|Impact of THz on 6G Wireless Communication

The 5G network, with its additional new techniques, such as millimeter wave, massive MIMO, beamforming, small cells, and full duplex, will offer revolutionary new features compared to previous generations. Nevertheless, the explosive growth in the number of connected systems could overcome the capabilities of $5 \mathrm{G}$ wireless networks. Some recently developed applications, such as virtual reality systems, are required to go beyond $5 \mathrm{G}$ because they need a minimum data rate of ten $\mathrm{Gbps}$, which exceeds the capacity of 5G systems [43]. In addition, high-definition video, ultrahigh-definition (UHD) devices, and 3-D video are becoming increasingly valuable for mobile users. Uncompressed UHD video can achieve $24 \mathrm{~Gb} / \mathrm{s}$ data rate, while uncompressed 3-D video with UHD can achieve $100 \mathrm{G} / \mathrm{ps}$ [26].

Research into the use of $\mathrm{THz}$ radiation in $6 \mathrm{G}$ wireless networks has become a daily occupation for researchers and players in the telecommunications field. This technology will revolutionize not only communication systems and their applications, but also business, personal life, lifestyle, and thus society [44]. To meet the expectations of the intelligent information society of 2030. China has launched the “Broadband Communications and New Networks” project for 2030 and beyond. The European Commission’s Horizon 2020 program has sponsored multiple B5G projects, like TERRANOVA; a project that aims to develop architectures and technologies capable of delivering optical network quality of experience in 6G wireless communication networks [45]. In the USA, the FCC has already launched studies of $6 \mathrm{G}$ networks, and the THz band has already opened. For the FCC, frequencies beyond $5 \mathrm{G}$ are reserved for 6G. In Japan, the first 6G projects have already been launched in 2020 [46]. Finland organized the first global summit on 6G wireless technology and launched the 6Genesis project, the first $6 \mathrm{G}$ project. The project supports the development of several aspects of wireless communication [47]. The International

电气工程代写|通讯系统作业代写communication system代考|VCO Design for THz Band

Various electronic and/or photonic systems and technologies have been developed to achieve the first demonstrations of THz communication. Due to the limitation of the operating frequency of the transistors developed by different foundries, most of the published works in the literature propose photonic solutions. Recently, electronic techniques are being developed, and our work is part of the development of an efficient wireless communication system for the terahertz frequency band.

Due to the behavior of passive elements at high frequencies, and the limited cutoff frequency for transistors, the VCO presents one of the most difficult blocks to design in a transceiver system. In this section, we propose the study and design of a $\mathrm{VCO}$, capable to generate a signal with frequencies around $104 \mathrm{GHz}$.

For the design of a local oscillator that delivers a high-power signal with minimal phase noise, we have opted for the pHEMT (pseudomorphic High Electron Mobility Transistor) of the PH15 process from the UMS foundry. It is characterized by a transition frequency $\mathrm{fT}=110 \mathrm{GHz}$ and a gate length of $0.15 \mu \mathrm{m}$ [48]. In this regard, considering the limitation of the operating frequency of most of the transistors developed so far, we have focused in this chapter on the choice of a structure that favors the second harmonic (Fig. 3). It consists of a LO (Fig. 4) whose fundamental oscillation frequency is $52 \mathrm{GHz}$ and a bandpass filter (Fig. 7), whose passband is around $104 \mathrm{GHz}$.

电气工程代写|通讯系统作业代写communication system代考|Impact of THz on 6G Wireless Communication

5G 网络及其附加新技术，如毫米波、大规模 MIMO、波束成形、小型蜂窝和全双工，将提供与前几代相比具有革命性的新功能。然而，连接系统数量的爆炸式增长可能会克服5G无线网络。一些最近开发的应用程序，例如虚拟现实系统，需要超越5G因为他们需要 10 的最低数据速率Gbps，这超过了 5G 系统的容量 [43]。此外，高清视频、超高清 (UHD) 设备和 3-D 视频对移动用户的价值越来越高。未压缩的超高清视频可以实现24 Gb/s数据速率，而 UHD 的未压缩 3-D 视频可以实现100G/ps [26].

广义线性模型代考

statistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。