满足数字RF技术迅猛发展的需求泰克推出新型实时频谱分析仪

泰克公司日前推出RSA6100A系列实时频谱分析仪，其提供的实时性能、捕获带宽和动态范围组合满足了广泛的尖端数字RF应用的需求。DPX^TM波形图像处理器技术把数量庞大的实时数据转化成实时的RF频谱演示，揭示以前看不到的RF信号和异常信号。与速度最快的扫频分析仪和矢量信号分析仪（VSA）相比，其频谱测量速率提高了近1000倍，实现了实时的RF。     

频谱分析仪的检定及装置的不确定度评定

频谱分析仪是常用的信号分析仪器,本文介绍了频谱分析仪的构成、工作原理,根据频谱分析仪的检定参数设计了频谱分析仪检定装置,并对装置的测量不确定度进行了评定,为频谱分析仪的检定工作不确定度的评定以及新的标准装置的研制提供参考。     

电磁干扰测试面临的挑战和实时技术

回顾通信技术的发展,并结合当今电子技术的特点和电磁环境的复杂性,针对EMI测试所面临的挑战,提出使用实时频谱分析技术.通过分析传统扫描频谱分析仪和实时频谱分析仪在硬件结构、检波方式和测试时间上的区别,论证了实时频谱分析技术在解决偶发信号和同频信号捕获上的优势；通过使用传统扫描频谱分析仪和实时频谱分析仪对瞬态信号的测试案例,直观感受到了实时技术在EMI测试中的准确性.     

基于LabVIEW的频谱分析仪测量调频频偏的方法

调频就是调制信号引起被调制载波的频率发生瞬时变化。频谱分析仪是一种在频率域对被测信号进行定量分析的仪器,通过对频谱分析仪的设置,可以利用它测量调频信号。本文研究了调频信号在频率域的信号特征,设计并实现了基于LabVIEW的频谱分析仪测量调频频偏的方法。一、调频信号的特征分析     

频谱分析仪自动校准中的问题及解决方式

频谱分析仪用于周期信号或准周期信号的频谱分析,广泛应用于通信、广播等行业,为了确认频谱分析仪的可靠性,每年都需要定期对其校准。频谱分析仪传统的校准方法中问题较多,如:校准方法不统一、校准指令不通用、被校准点不可更改。针对这些问题,本文提出了频谱分析仪自动校准软件解决方式,所设计的自动校准系统可对多品牌、多系列的频谱分析仪做自动校准,自动查找识别仪器、智能校准、生成原始记录和证书、功能可扩展等。该校准系统智能、高效、可靠。     

RFID测试仪调制指数测量方法

介绍了RFID技术在国内的计量现状和RFID系统的工作原理,详细分析了RFID标签产品在不同频段范围内的应用情况,提出了RFID测试仪的主要计量参数,着重介绍了数字调制指数的测量。根据RFID信号的帧结构和数字调制方式的定义,从理论上分析了调制指数的测量方法,提出使用数字实时示波器和矢量信号分析仪两种方法进行调制指数的测量,介绍了测量方法和注意事项,并对两种方法的测量结果进行了测量不确定度评定。结果表明,矢量信号分析仪比数字实时示波器更适用于RFID测试仪调制指数的测量。     

JJF1396-2013《频谱分析仪校准规范》的解读

正一、规范修订的背景及目的频谱分析仪的计量技术法规JJG501-1987《频谱分析仪检定规程》最早于1987年发布实施,2000年对其作了重新修订,被JJG501-2000《频谱分析仪检定规程》代替。随着电子测量技术的不断发展,频谱分析仪的频域测量技术不断改进,频率测量范围不断拓宽,测量准确度不断提高,测量功能也不断增多。而原检定规程的频率测量范围只覆盖到26.5 GHz,且某些测量方法已无法对新型频谱分析仪实现科学合理的计量。因此,需要重新修订检定规程,以更宽的频率覆盖范围和更科学合理的测量方法来满足频谱分析仪的计量需求。     

利用远程桌面控制FSV信号频谱分析仪

针对利用Windows XP远程桌面控制FSV信号频谱分析仪的问题,介绍了FSV信号频谱分析仪端设置,控制器端设置、启动和终止远程操作方法,以及使用过程中需要注意的问题,对充分利用FSV信号频谱分析仪及其具有类似功能的仪器,提高工作效率,具有重要的参考价值。     

JJF1396-2013《频谱分析仪校准规范》的解读

正一、规范修订的背景及目的频谱分析仪的计量技术法规JJG501-1987《频谱分析仪检定规程》最早于1987年发布实施,2000年对其作了重新修订,被JJG501-2000《频谱分析仪检定规程》代替。随着电子测量技术的不断发展,频谱分析仪的频域测量技术不断改进,频率测量范围不断拓宽,测量准确度不断提高,测量功能也不断增多。而原检定规程的频率测量范围只覆盖到26.5GHz,且某些测量方法已无法对新型频谱分析仪实现科学合理的计     

接收机测量谐波的方法及优缺点分析

本文提出了一种采用测量接收机HP8902A测量射频信号源谐波的方法,对该方法的特点及应用范围进行了分析与说明,并通过与常规的频谱分析仪测量谐波的方法进行比较,确定了该测量方法的可行性,可以用于没有频谱分析仪的情况下射频信源谐波的检定。     

An inference monitor with real-time FFT spectral analysis for aradio observator

A system is described which uses a real-time fast Fourier transform (FFT) spectrum analyzer to monitor radio interference near 408 MHzs occurring at a radio observatory. Direction of arrival, frequency, intensity, and time of occurrence are recorded under the control of a microcomputer. A sensitive receiver can be connected to any one of eight directional antennas to establish direction of arrival. The receiver output is digitized to 8 b, and analyzed by the FFT spectrum analyzer which has a real-time bandwidth of 0.5 MHz. A total bandwidth of 20 MHz is analyzed in segments of 0.4 MHz. The analyzer uses the modified periodogram method developed by P.D. Welch (IEEE Trans. Audio Electroacoust., vol.AU-15, p.70-3, June 1967), and a Kaiser-Bessel windowing function is applied to ensure low sidelobes. Dynamic range is 40 dB, and the interference monitor obtains high sensitivity to very weak interfering signals by time averaging. Several general design principles which arise out of certain constraints are elucidated. Some new results are presented concerning the detectability of small signals by FFT processors     

Effect of Spectrum Analyzer Filtering on Electromagnetic Dosimetry Assessment for UMTS Base Stations

While many different measurement techniques and simulation tools are available to assess electromagnetic exposure for second-generation mobile communications base stations, few works have tackled the problem for downlink third-generation (3G) universal mobile telecommunications system (UMTS) signals. In this paper, deep analyses of the effect of spectrum analyzer (SA) filtering on 3G/UMTS field measurement for electromagnetic compliance assessment are presented. A procedure for evaluating compliance of frequency-division duplex 3G/UMTS Node B to electromagnetic safety limits, avoiding the use of a code-domain analyzer, is also presented and discussed. Adequate SA settings for exposure compliance testing are proposed, and an important relationship between resolution and video bandwidths is found, which dominates analyzer settings effects on final 3G/UMTS exposure assessment results.     

High sensitivity noise measurement with a correlation spectrumanalyzer

A spectrum analyzer with enhanced sensitivity has been built and used in noise measurements. It is based on the processing of the input signal by two independent channels in parallel and takes advantage of the incoherent property of the noise in each of the two input stages. The instrument has demonstrated an improvement in sensitivity of at least 50 dB with respect to a traditional system, and therefore can measure low input signals down to the hundred pV/√Hz range     

A PC-based vibration analyzer for condition monitoring of processmachinery

A fast-response PC-based vibration analyzer has been developed for fault detection and preventive maintenance of process machinery. The analyzer acquires multiple vibration signals with high resolution, and computes frequency spectra, root mean square amplitude, and other peak parameters of interest. Fast execution speed has been achieved by performing data acquisition and frequency spectrum computation using C-language. Vibration signals up to 10 kHz can be analyzed by the spectrum analyzer. Special algorithms, such as window smoothing, digital filtering, data archiving and graphic display have also been incorporated. With these features the vibration analyzer can perform most of the functions available in complex, stand-alone machines. The software for the analyzer is menu driven and user-friendly. The personal computer used is a 66 MHz PC-486 compatible machine. The use of a general purpose PC and standard programming language makes the vibration analyzer simple, economical, and adaptable to a variety of problems. The applications of the system in malfunction detection in rotating machinery are also described     

A real-time electro-optic handy probe using a continuous-wave laser

This paper describes a real-time electro-optic (EO) probe system that can be directly connected to digital oscilloscopes, spectrum analyzers, and other widely used instruments. The probe incorporates a balanced optical receiver with two high-speed InGaAs p-i-n photodetectors (PDs) to reduce noise, and optical isolators to decrease the light reflected from the optics back to the laser diode (LD). To increase sensitivity, we employ cadmium telluride (CdTe), which has a large EO coefficient, and a high-power 1.3-μm distributed-feedback (DFB) LD as a continuous-wave (CW) laser source. We used it to measure eye diagrams at 1 Gb/s that were displayed on a digital oscilloscope. In addition, when connected to a spectrum analyzer, the probe significantly simplifies frequency-domain analysis. We demonstrate the measurement of electric nearfield distribution radiating from a two-layer printed circuit board (PCB) and a cellular phone. The result shows that the probe system is a potential candidate for electromagnetic interference (EMI) instruments     

A CCD-Based Real-Time Spectrum Analyzer for Incoherent Scatter Radar Systems

A real-time spectrum analyzer based on a charge-coupled device (CCD) is described. The power spectrum is calculated by the chirp z-transforn using the CCD. The analyzer includes a buffer memory for the input data and an integrator to sum the computed spectral estimates for better statistical accuracy. The analyzer makes one 512-point, discrete Fourier Transform (DFT) for complex data in 1.024 ms.     

一种基于光拍频的连续激光调制光谱测量方法

针对F-P干涉仪分析连续激光调制光谱的局限性,本文提出了一种基于光拍频的连续激光调制光谱的测量方法,该方法可实现调制频率低达千赫兹的连续激光调制光谱的测量.本方法以光电转换理论为基础,利用频谱分析仪测得参考光与连续调制光谱的拍频信号,然后通过相应的数学计算得到连续调制光谱的各个光频的相对电场强度,从而实现连续调制光谱的分析.本文在理论建模与分析的基础上,利用该方法对半导体激光器出射激光经电光调制器调制产生的调制光谱进行了测量,测量结果与F-P干涉仪测量结果一致,验证了该方法的可行性.     

Wavelet power spectrum-based autofocusing algorithm for time delayed and integration charge coupled device space camera

A novel autofocusing algorithm using the directional wavelet power spectrum is proposed for time delayed and integration charge coupled device (TDI CCD) space cameras, which overcomes the difficulty of focus measure for the real-time change of imaging scenes. Using the multiresolution and band-pass characteristics of wavelet transform to improve the power spectrum based on fast Fourier transform (FFT), the wavelet power spectrum is less sensitive to the variance of scenes. Moreover, the new focus measure can effectively eliminate the impact of image motion mismatching by the directional selection. We test the proposed method's performance on synthetic images as well as a real ground experiment for one TDI CCD prototype camera, and compare it with the focus measure based on the existing FFT spectrum. The simulation results show that the new focus measure can effectively express the defocused states for the real remote sensing images. The error ratio is only 0.112, while the prevalent algorithm based on the FFT spectrum is as high as 0.4. Compared with the FFT-based method, the proposed algorithm performs at a high reliability in the real imaging experiments, where it reduces the instability from 0.600 to 0.161. Two experimental results demonstrate that the proposed algorithm has the characteristics of good monotonicity, high sensitivity, and accuracy. The new algorithm can satisfy the autofocusing requirements for TDI CCD space cameras.     

基于小波能谱和小波信息熵的管道异常振动事件识别方法

提出了基于小波能谱和小波信息熵的油气管道异常振动事件识别方法。基于Mach-Zehnder光纤干涉仪原理的分布式光纤油气管道安全监测系统实时检测管道沿途振动信号,对测量的时间序列进行小波变换,根据小波系数计算小波能谱与小波信息熵,通过小波能谱和小波信息熵值两种测度识别不同的管道安全异常事件。港枣线成品油管道的现场实验结果表明,该方法可以快速有效地识别管道周围发生的泄漏及其他异常情况,其总体识别准确率达到98.5%,有效降低了误报警率,具有较强的在线工况识别能力。     

An Improved Method for the Evaluation of Uncertainty of Channel Power Measurement With a Spectrum Analyzer

This paper discusses issues in the uncertainty of power measurement performed with a superheterodyne spectrum analyzer. In particular, the channel power technique is considered, and an original and effective method is proposed based on the "Guide to the Expression of Uncertainty in Measurement" for the uncertainty evaluation of channel power measurement. The method is based on the measurement of some suitable parameters associated to the input signal's spectrum and the use of a proper postprocessing formula. It allows a user to greatly simplify the computation of measurement uncertainty without loss of accuracy. The effectiveness of the method is verified experimentally. In particular, experiments are performed involving both laboratory- generated signals and some typical real-world digital communication signals. Helpful information and hints for the optimization of the spectrum analyzer setup and the reduction of uncertainty are Anally provided.