Measurement of the linewidth enhancement factor in DFB lasers using a high-resolution optical spectrum analyzer

Linewidth enhancement factor (also know as chirp parameter is calculated for two distributed feedback lasers using the linewidth asymptotic behavior predicted by Schawles-Townes and Henry. A high-resolution optical spectrum analyzer (BOSA) is used to measure power and linewidth. Comparison with widely accepted network analyzer method is performed with very good agreement.     

使用频谱分析仪

有线电视技术人员一般会有频谱分析仪可供使用,用这种仪器来测量噪声是很方便的。在不扫频(零频距)时,频谱分析仪是一个固定调谐的选频电压表(见图3)。在扫频时,频谱分析仪直接显示某一频率范围内一系列零频距测量的结果。当频谱分析仪显示功率时,实际上是从实测电压换算而得的。     

Superconductive chirp-transform spectrum analyzer

Spectral analysis over an instantaneous bandwidth of 2.4 GHz has been demonstrated utilizing superconductive dispersive delay lines in a chirp-transform configuration. Two-tone resolution of 43 MHz and ±1.2-dB amplitude uniformity were achieved.     

A short-time spectrum analyzer with polyphase-network and DFT

Two algorithms for digital spectral analysis are compared: the conventional DFT, and a generalized polyphase principle, which is implemented by connecting a polyphase network to an FFT processor.Close relations as well as essential differences between these two analyzers are demonstrated, using the concept of multirate systems.A hardware realization of the system, capable of handling audio frequencies, is described briefly, and its practical performance is shown to agree with theory. Details on measurements as well as applications will be reported in a companion paper [20].     

在频谱仪上建立频谱数据库

频谱仪的应用很广泛,对于我们无线电管理部门来说,监测、检测、干扰分析等工作都可以利用它.现介绍我站对于频谱仪的一种用法. 我们尝试在频谱仪中建立频谱数据库.现以R/S公司的FSP13型频谱仪为例,介绍一下这种用法(无需安装键盘、鼠标).     

Selecting an optical spectrum analyzer

One of the most common measurement instruments found in a modern optics laboratory is the optical spectrum analyzer (OSA). These instruments measure the optical power spectrum of light emitted from optical sources, as well as light generated from optical interactions with matter. OSAs are based on several technologies. Each technology offers strengths, but also has limitations. Choosing the correct technology for a measurement application requires understanding the concepts of sensitivity (the ability to measure low power optical signals), dynamic range (the ability to measure low power signals), resolution (the ability to measure two signals separated by a small wavelength difference), amplitude accuracy (the ability to measure the absolute optical power present), and wavelength accuracy (again, the absolute value)     

Lensless integrated optics spectrum analyzer

An electrooptic integrated optics spectrum analyzer is investigated in which an electrode array with a spatially varying period performs the functions of the collimation and transformation lenses and of the signal introduction. The device yields a weighted discrete Fourier transform (DFT) of the voltages on the electrodes. An implementation of the device would be fully compatible with planar photolithographic processes.     

浅析频谱分析仪的动态范围

频谱分析仪的动态范围一般用dB表示，表征频谱分析仪输人端口能同时存在的最大信号与最小信号之间的比率。最小信号指的是在给定不确定度情况下，频谱分析仪所能测量的最小信号。     

The high-resolution spectrum estimator—A subjective entity

It is shown by example that the attribute of high resolution for a spectrum estimator can be a subjective one. The particular spectrum estimator considered is the MUSIC algorithm, although the observations are valid for any spectrum estimator. The main point is that visual examination of spectra is not a scientifically valid means of assessing resolution.     

实现宽带信号实时测频的声光频谱分析仪

针对日益复杂的电磁波环境,为突破工程可实用化的关键技术,对声光频谱分析仪进行高灵敏度、大带宽、实时响应等多方位技术攻关.阐述了高灵敏度、宽带、实时声光频谱分析仪的主要工作原理及设计方法.研制出瞬时带宽200 MHz,灵敏度优于-80 dBm,测频分辨率达1 MHz的声光频谱分析仪样机.若采用5通道同时工作,便可将带宽拓展到1 GHz,这将在电子战中具有很高的应用价值.其中,详细介绍了采用超声跟踪方式拓展声光偏转器布喇格带宽的设计以及在视频信号处理电路中首次采用的频点跟随读数方式.此种数据采集方式避免了传统设计中靠微机对信号进行处理、检出等繁琐环节所造成的时间拖延,真正做到信号的实时响应输出.     

A folded-type integrated-optic spectrum analyzer using butt-coupled chirped grating lenses

A folded-type integrated-optic spectrum analyzer (IOSA) using reflection-type chirped grating lenses butt-coupled to a LiNbO3waveguide Bragg cell is presented. The lenses can be easily fabricated by the well-established planar process, and the IOSA has good performance as well as a reduced device length. The spectrum analyzer function of 4.0 MHz resolution in 95-345 MHz RF frequency range is demonstrated.     

如何对新设寻呼系统进行验收测试

验收测试是指对新设无线寻呼系统初装设备或原有系统更新设备进行实地检测;对系统（网络）优化覆盖及可靠性进行实地测定。主要目的是确定系统设备的主要技术参数是否满足国家标准（GB／T15938－1995）要求;掌握和评估系统覆盖区域接收可靠性及可能存在的干扰情况,发现问题、找出原因、及时整改,为无线电科学管理提供技术保证。　　在对新设无线寻呼系统进行验收测试的实践中,我们形成了一套行之有效的操作方法,这里作简单介绍,供同行参考。 一、验收测试前的准备　　1．根据用户提供的系统组网方案,对新设寻呼系统设备的分布及地…     

无线频谱分析仪的选择

无线设备在工作时可能会出现周期性地挂起,干扰其他消费电子产品的工作（例如电台）,或者无法完全发挥应有的功能,这些问题都会使消费者对它的技术水平和相应的产品供应商丧失信心。为了避免这种糟糕的情况,选择一种能够满足当今无线产品设计与调试需求的高性能频谱分析仪是至关重要的,这种频谱分析仪不仅要能够检验产品的真实性能,也要能够检测高度集成的无线发射器的功能。     

A real-time, low-power implementation for high-resolution eigenvalue-based spectrum sensing

In this paper, a novel multiple antenna, high-resolution eigenvalue-based spectrum sensing algorithm based on the FFT of the received signal is introduced. The proposed platform overcomes the SNR wall problem in the conventional energy detection (ED) algorithm, enabling the detection of the weak signals at ?10 dB SNR. Moreover, the utilization of FFT for the input signal channelization provides a simple, low-power design for a high-resolution spectrum sensing regime. A real-time, low-area, and low-power VLSI architecture is also developed for the algorithm, which is implemented in a 0.18 μm CMOS technology. The implemented design is the first eigenvalue-based detection (EBD) architecture proposed to-date capable of detecting weak signals at ?10 dB. Despite having more algorithmic complexity in comparison to the ED, the proposed EBD architecture shows no significant increase in the core area and the power consumption, due to the FFT utilization for the input signal channelization. The proposed design occupies a total area of 3.4 mm² and dissipates 78 mW for a 40 MHz sensing bandwidth consisting of 32 sub-channels.     

Optical spectrum analyzer utilizing MEMS scanning mirror

An optical spectrum analyzer (OSA) has been newly developed by the authors, utilizing a microelectromechanical system scanning mirror with 1.7-ms scan speed for the C-band and a wavelength resolution of 10 pm. This new OSA is suitable for wavelength-division-multiplexing performance monitoring that requires high speed and high wavelength resolution.     

基于DDS的频谱分析仪设计

设计了基于直接数字频率合成(DDS)的频谱分析仪.它依据外差原理,实现频率范围为1～30 MHz的信号频谱分析.通过采用DDS专用器件AD9851产生稳定的扫频信号.被测信号是经AD835与本振信号混频,再放大,滤波,检波的信号.将被测信号与扫频信号分别输入示渡器的X,Y端,即可获得频谱图.此外,该仪器还具有识别调幅,调频和等幅波信号及测定其中心频率的功能.     

Integrated optical spectrum analyzer with internal gain

The first scanning integrated optical spectrum analyzer (IOSA) with resolution enhancement due to intracavity loss compensation in an amplifying Ti:Er:LiNbO₃-waveguide is reported. The active IOSA of about 1.423 GHz free spectral range has been diode-pumped at λ_p=1479 nm (E_p∥c) slightly below the lasing threshold at 1531 nm (P_p,th≅40 mW). Linear scanning of the cavity resonances has been achieved by driving the phase modulator (U_x≅10.4 V) with a sawtooth voltage. A finesse up to 205 has been achieved at λ_s≅1546 nm     

基于FPGA的简易频谱分析仪

观测信号频谱在科研中具有重大意义,在教学实验中也有利于学生更直观深入地了解信号特征。采用单片机C8051和FPGA,外加高速A／D转换器设计一种简易的频谱分析仪。该系统主要包括信号采集、频谱搬移、数字滤波、数字FFT和LCD显示。经测试,该系统能够分析信号带宽为0～5MHz,最低分辨率达到1Hz。而且信号频谱图能够很好地显示在LCD上。整个系统工作稳定,操作方便,且成本比其他频谱分析仪低很多。     

基于FPGA的简易频谱分析仪

观测信号频谱在科研中具有重大意义.在教学实验中也有利于学生更直观深入地了解信号特征.采用单片机C8051和FPGA.外加高速A/D转换器设计一种简易的频谱分析仪.该系统主要包括信号采集、频谱搬移、数字滤波、数字FFT和LCD显示.经测试.该系统能够分析信号带宽为0～5 MHz,最低分辨率达到1 Hz.而且信号频谱图能够很好地显示在LCD上.整个系统工作稳定,操作方便,且成本比其他频谱分析仪低很多.