双通单色仪在高性能光谱分析仪中的应用

主要讲述了双通单色仪的工作原理,以及它在高性能光谱分析仪中的应用。用它可以实现对被测光大动态范围和小偏振相关度的测量。     

Planar microoptomechanical waveguide switches

Planar micromechanical waveguide switches based on lateral deflection of a cantilever beam are presented. Two material systems have been used: a GaAs-AlGaAs structure with integrated waveguides and a silicon-on-insulator (SOI), with postprocessed polymeric waveguides. The switches are characterized by low actuation voltage (3-20 V), short switching times (32-200 μs), and low crosstalk (< -30 dB)     

PC-based spectrum analyzer

The design and performance analysis of a low-cost, low-frequency spectrum analyzer are described. This instrument has been conceived as a plug-in board to be incorporated in an IBM PC. Although intended primarily for educational purposes, this analyzer is suitable for other applications such as audio, vibrations, etc. The frequency synthesizer, superheterodyne, and harmonics identifier used in the spectrum analyzer are discussed     

一种手持式频谱分析仪的设计与实现

为适应野外作业对频谱测量的需求,研制手持式频谱分析仪。通过采用软件无线电设计思想,在超外差接收后直接进行A/D采样,将频谱功能实现数字化,节省了体积与功耗,实现了性能指标较高的手持式频谱仪。     

A spectrum analyzer laboratory project

A laboratory project in which the students build a simple DC1 MHz spectrum analyzer using only an oscilloscope, function generator, and a custom built-mixer/IF section is described. After assembling the spectrum analyzer, the students use it to explore the spectra of a number of different waveforms including amplitude- and frequency-modulated sine waves. The laboratory helps the students develop a feel for the meaning and significance of the mathematics they have learned relating the time- and frequency-domain representations of signals (i.e., the Fourier series, and Fourier and Laplace transforms). In addition, the laboratory introduces the students to mixing (i.e., heterodyning) and improves their understanding of their test equipment and its possible uses. The laboratory is suitable for use in a typical junior-level signals and systems course, a junior-level circuits course, a communication course, or a measurement course     

Eb／n0的频谱分析仪测量方法

Eb／n0是衡量接收机性能的重要指标之一,但难以直接测量。在分析Eb／n0与S／N之间关系的基础上,推导出二者的数学换算式,从而得出可通过测量信号功率S和噪声功率N,再经计算得到Eb／n0的理论依据。详细阐述了实际使用频谱分析仪进行S和N测量的方法和具体操作步骤,对该测量方法进行了实验验证并简要分析了测量不确定度来源。     

利用VC++.NET中MSComm控件的频谱仪通信软件设计

Visual C .NET 2003中的MSComm控件提供了一系列标准通讯命令,利用MSComm控件实现的仪表串口通信可以很方便地对仪表发送控制命令、进行数据交换.本文给出了在Visual C .NET 2003中用MSComm控件开发仪表通信软件的具体实现步骤,实现了仪表和计算机的良好通信.该程序在某雷达电磁环境监测系统中,能够稳定运行,并实现了通过电脑进行实时监控的功能,具有一定的应用价值.     

EO polymer-based integrated-optical acoustic spectrum analyzer

An acoustic spectrum analyzer based on electrooptic (EO) polymer integrated optics is presented. The device is used in a scanning heterodyne geometry by zero biasing a Michelson interferometer. It is capable of detecting vibrations from DC to GHz range. The novelty of the work is applying EO polymers to high frequency acoustic sensing applications. EO polymers have been extensively used for communication devices. However, their use in high frequency sensing applications remains unexplored. The sensor presented is designed to analyze thin film structure by utilizing high frequency capabilities of EO polymers. The advantage of this approach over existing methods is in its potential to detect vibrations over 100 GHz with low drive voltages (V_π less than 1 V), using a device that is completely electrically controlled with no mechanical moving parts. Low frequency tests indicate good agreement between experimental results and theoretical predictions. Acoustic vibrations excited by pulsed Nd-YAG laser are detected to frequencies up to 200 MHz using the device presented     

利用频谱分析仪进行电磁干扰预测试

电子产品的电磁干扰经常在屏蔽暗室进行测量甚至调试,往往带来高昂的费用,而在测量前利用频谱分析仪来进行预测试,可以有效的缩短暗室的调试测量时间,从而降低成本。RIGOL的DSA815频谱分析仪具有准峰值检波和EMI测量功能,用近场探头或天线探测被测设备,可以快捷的对被测设备的电磁干扰情况进行预测试。     

频谱分析仪中扫描时间和相关参数的解析

在超外差频谱分析仪中,当其分辨率带宽为模拟带宽时,频谱分析仪的扫描时间受很多因素的影响,在用户使用时要合理地设置各个参数,才能取得最好的测量效果。本文将以中频滤波器为类高斯滤波器为模型,着重介绍扫描时间与扫频宽度、分辨率带宽以及视频带宽之间的关系。从频域和时域推倒出这些参数之间的数学公式。从而使读者更深刻理解频谱分析仪些参数的关联性。     

Gain stabilization in a quantum‐dot semiconductor optical amplifier using tapered waveguide structure

In this paper, transient gain of a quantum‐dot semiconductor optical amplifier (QD‐SOA) is studied. Waveguide of the QD‐SOA is considered to have a tapered structure in which width of the waveguide increases along the QD‐SOA. It is observed that by employing tapered waveguide, gain as the key feature of the device acquires more stability, investigated by studying the impact of a powerful optical pulse on the gain as it passes through the amplifier. Thus, by gradually increasing the width of the waveguide along QD‐SOA active region, drop in the gain, caused by the strong pulse, decreases. Transient gain of the device is obtained for several outputs to input width ratios. It is demonstrated that as the width ratio increases, gain stability improves drastically; as for width ratio of 10, stability increases over 10 times compared with the generic QD‐SOA. In addition to the gain, cross‐gain modulation as a nonlinear process, which depends on the gain instability imposed by strong pulses, is studied. In this paper, the rate equations are employed for modeling tapered waveguide QD‐SOA. MATLAB ODE (MathWorks, MA, USA) along with the finite difference method is used for studying and simulating the device. Copyright © 2013 John Wiley & Sons, Ltd.     

All-optical logic gates by using multibranch waveguide structure with localized optical nonlinearity

We propose all-optical logic gates by using a multibranch waveguide structure with localized optical nonlinearity. By simply setting nonlinear media in the selected output guides and properly launching the input power, the numerical results show that the proposed all-optical waveguide structure could really function as AND and OR logic gates.     

A low-frequency digital spectrum analyzer for laboratoryinstruction

The design and implementation of a low-frequency spectrum analyzer is described. The design features a low-cost spectrum analyzer for use in the electrical engineering senior year communications laboratory. The frequency range of the spectrum analyzer extends from under 1 Hz up to 20 kHz. It covers the spectral region of interest in speech processing and baseband data transmission, and provides the students with a flexible signal analysis tool     

频谱分析仪中频带宽的设计

本文介绍了一种应用于高性能频谱分析仪的,中心频率不变,带宽可程控并可连续调节的中频滤波器的设计原理与实现方法。对其中的主要模块进行了详细讨论,并给出了仿真与实验结果。     

实时频谱分析仪中重叠帧频谱分析技术研究

针对实时频谱分析仪缺乏微弱信号检测能力问题,提出了重叠帧频谱分析技术.该方法既可以获取信号局部频谱的精细结构,又可以提高快速傅里叶变换（FFT）相参积累的增益,从而提高对微弱信号的检测能力.介绍了重叠帧频谱分析技术的基本原理,详细讨论了重叠因子设计准则,在此基础上,提出了实现该技术的设计方案.该方案成功地在研发实时频谱分析仪过程中得到实现.通过实验验证,相比普通频谱分析技术,重叠帧频谱分析技术能达到光谱图中展宽信号时域显示的功能,且对微弱信号,在相同检测概率下,对信噪比（SNR）要求降低至少2 dB.     

频谱分析仪测量相位噪声及测量不确定度分析

相位噪声是电子测量中的一个重要指标,相噪指标的好坏直接影响着整个系统的性能。测试相位噪声的方法有几种,然而,每种测试方法都有各自的优缺点。因此,根据实际的需要来选择适当的测试方法就尤为重要。本文主要是通过实验来讨论用频谱分析来测量相位噪声的方法,并对其测量的结果,应用不确定度理论给出了相应的测量不确定度的分析。     

频谱分析仪中数字中频滤波器的实现

本文首先简述了分辨率和中频滤波器概念,然后详细描述了数字中频滤波器的实现原理,最后介绍了数字中频滤波器在DSP芯片TMS320C6701上的运用.实际应用结果说明,数字中频滤波器比模拟滤波器在可实现最小分辨率带宽、滤波器波形因子、测量速度等方面都具有很大的优势.     

频谱分析仪在测量过程中的优化使用

为了在测量中高效使用频谱分析仪,需要对其进行优化设置。主要阐述了如何在测量过程中根据测试目的优化设置频谱分析仪相关参数和状态,以获得高的测量精度、快的测量速度和大的动态范围从而达到优化使用频谱分析仪、提高测量效能的目的。     

Polymeric optical waveguide films for short-distance opticalinterconnects

We describe three different applications of polymeric waveguide films as short-distance optical interconnects. We fabricated the waveguide films, which were 6.5 cm long and mounted in MT-compatible (MTC) connectors by passive alignment, for MM fiber systems with a 50-μm diameter graded index (GI) core. The average insertion loss of these devices was approximately 0.6 dB at 0.85-μm wavelength. We also fabricated waveguide films with a 350 mirror and an MTC connector for use as 90° out-of-plane optical deflectors, and they exhibited an insertion loss of 1 dB. Two silica planar waveguides for single-mode (SM) fiber systems were also connected by a polymeric waveguide film. Low insertion losses were obtained in both MM and SM films designed to be employed as bending waveguides. This reveals their good potential for use as practical short-distance optical interconnects     

EMI接收机与频谱仪的校准

本文从超外差式EMI接收机和频谱仪的原理和结构入手,在介绍常见的超外差式EMI接收机和频谱仪的主要技术指标的基础上,分析了这两类仪器校准方法的异同。作者从这两类仪器的使用目的对差异较大的校准参数进行分析,构建了相应的校准方法。这些方法是在大量实验的基础上完成的,对于EMI接收机特别重要的脉冲响应的校准,文中给出了具体的校准数据,结合数据分析了EMI接收机与频谱仪的最重要差别,并总结出Agilent公司的预选器N9039+PSA频谱仪方案是完全满足CISPR标准的全兼容接收机。