Redshift Anomaly of the 2292 MHz Radio Signal Emitted by the Pioneer-6 Space Probe as Multiple Interactions with Photo-Ionized Electrons in the Solar Corona

This paper calculates the redshift of the 2292 MHz radio photon emitted by the Pioneer-6 space probe. The signal crossed the solar corona on the days close to the solar occultation between November and December 1968, the only ones for which scientific data are available, until it reached a terrestrial radio receiver. The specific study is based on a calculated orbital model of the Earth and Pioneer-6 system made on a scale of 1:100,000 by a CAD, on the New Tired Light theory adapted to the geometric and physical configuration of the topic and on a computational method. Removing the Doppler shift contributions of proper and rotational motions, due to the set-up of the receiver, and excluding the recombination factor of neutral hydrogen, which is irrelevant for distances within 1 AU, the calculation of the redshift can be traced back to the interactions between the radio signal and the electrons of the solar corona alone. The latter are contained in a Stroemgren sphere and photo-ionized by solar radiation in the UV and X-ray range. Furthermore, in order to have an interactional redshift contribution, the electrons have to satisfy the Wigner-Crystal Precondition for which their unitary potential energy is greater than their kinetic energy. Otherwise, a Thomson scattering process takes place in which the energy of the radio photon remains unchanged. The comparison between the gravitational redshift together with the interactional redshift detected from this study methodology and the total redshift obtained from other scientific studies shows a similarity between the curves, including the observational data, both in terms of values, trend of the graphs and single punctual variations.

Anomalies Observed in VLF and LF Radio Signals on the Occasion of the Western Turkey Earthquake(M_(W)=5.7)on May 19,2011

Since 2009 a network of VLF (20 - 60 kHz) and LF (150 - 300 kHz) radio receivers is operating in Europe in order to study the disturbances produced by the earthquakes on the propagation of these signals. In 2011 the network was formed by nine receivers, of which three are located in Italy and one is in Austria, Greece, Portugal, Romania, Russia and Turkey. On May 19, 2001 an earthquake (Mw = 5.7) occurred in western Turkey, that is inside the “sensitive” area of the network. The radio data collected during April-May 2011 were studied using the Wavelet spectra, the Principal Component Analysis and the Standard Deviation trends as different methods of analysis. Evident anomalies were revealed both in the signals broadcasted by the TRT transmitter (180 kHz) located near Ankara and in a VLF signal coming from a transmitter located in Western Europe and collected by the receiver TUR of the network located in eastern Turkey. Evident precursor phases were pointed out. Some differences in the efficiency of the three analysis methods were revealed.

Direction of Arrivals Estimation for Correlated Broadband Radio Signals by MVDR Algorithm Using Wavelet

A theoretical relationship between the wavelet transform and the fast fourier transformation(FFT) methods in broadband wireless signal is proposed for solving the direction of arrivals(DOAs) estimation problem. This leads naturally to the derivation of minimum variance distortionless response(MVDR) algorithm, which combines the benefits of subspace methods with those of wavelet, and spatially smoothed versions are utilized which exhibits good performance against correlated signals. We test the method's performance by simulating and comparing the performance of proposed algorithm, FFT MVDR and MVDR with correlated signals, and an improved performance is obtained.

Variations of VLF radio signals and atmospherics during the deep earthquake with M = 8.2 occurred on 24 May 2013 near Kamchatka peninsula

To detect seismic disturbances in the lower ionosphere, we have used the signals of very-lowfrequency radio transmitters and natural radio signals—electromagnetic emission of lightning discharges—atmospherics. On earlier results of observation of atmospherics, it was obtained that the earthquake effects are displayed as weight-hourly amplitude increases on the day of event or within 3 days after them. Possible earthquake precursors are also manifested as one-day (within one to several hours) increases in the amplitude of atmospherics on average 5 - 12 days before the event. Analysis shows that seismic effects in the amplitude of atmospherics have been observed in the case of sufficiently strong (magnitude M > 4.5) and not very deep (usually no deeper than 50 km) earthquakes. The effects of the events of the earthquake with magnitude of 8.2 occurring in the Sea of Okhotsk on 24.05.13 not far from the Kamchatka Peninsula at a depth of 609 km considered in this work have shown that even deep earthquakes may have precursors in the form of disturbances in the lower ionosphere.

Large-scale real-world radio signal recognition with deep learning

In the past ten years, many high-quality datasets have been released to support the rapid development of deep learning in the fields of computer vision, voice, and natural language processing. Nowadays, deep learning has become a key research component of the Sixth-Generation wireless systems(6G) with numerous regulatory and defense applications. In order to facilitate the application of deep learning in radio signal recognition, in this work, a large-scale real-world radio signal dataset is created based on a special aeronautical monitoring system-Automatic Dependent Surveillance-Broadcast(ADS-B). This paper makes two main contributions. First, an automatic data collection and labeling system is designed to capture over-the-air ADS-B signals in the open and real-world scenario without human participation. Through data cleaning and sorting, a high-quality dataset of ADS-B signals is created for radio signal recognition. Second, we conduct an in-depth study on the performance of deep learning models using the new dataset, as well as comparison with a recognition benchmark using machine learning and deep learning methods.Finally, we conclude this paper with a discussion of open problems in this area.

The Refractive Effect of k-Factor on Radio Propagation over Lokoja, Nigeria

The effective earth radius factor(k-factor)has a refractive propagation effect on transmitted radio signals thus making its study necessary for the proper planning of terrestrial radio links and power budget.This study was carried out over the city of Lokoja,Nigeria,using ten years(2011 to 2020)atmospheric data of temperature,pressure and humidity both at the surface(12 m)and at 100 m AGL.The data were retrieved from European Centre for Medium-Range Weather Forecasts(ECMWF)ERA5.The k-factor yearly variation follows the same trend with minimum and maximum values obtained during dry and wet season months respectively.In addition,the highest mean value of 1.00042 was recorded in the month of August while the lowest value of 1.00040 was recorded in the month of January with an overall mean value of 1.0003.This value is less than the recommended standard of 1.33 by ITU-R.The propagation effect corresponding to k<1.33 is sub-refractive.The implication of this on radio wave propagation,especially terrestrial communications is that transmitted wireless signal is prone to losses.This can be mitigated through an effective power budget:Choice of transmitting antenna’s height and gain,so as to improve the Quality of Service over the study area.

A New Signal Processing Technique of π/4-DQPSK Modem Based on Software Radio

DQPSK modem has been chosen as the modem scheme in many mobile communication systems. A new signal processing technique of π/4-DQPSK modem based on software radio is discussed in this paper. Unlike many other software radio solutions to the subject, we choose a universal digital radio baseband processor operating as the co-processor of DSP. Only the core algorithms for signal processing are implemented with DSP. Thus the computation burden on DSP is reduced significantly. Compared with the traditional ones, the technique mentioned in this paper is more promising and attractive. It is extremely compact and power-efficient, which is often required by a mobile communication system. The implementation of baseband signal processing for π/4-DQPSK modem on this platform is illustrated in detail. Special emphases are laid on the architecture of the system and the algorithms used in the baseband signal processing. Finally, some experimental results are presented and the performances of the signal processing and compensation algorithms are evaluated through computer simulations.

A Virtual TDOA Localization Scheme of Chinese DTMB Signal in Radio Monitoring Networks

As the radio communications technology widely used,wireless location technology plays a more important role in maintaining the order of the air waves.However concretely effective symbol calibration method with regard to Chinese DTMB signal of different frame mode is quite under research due to the multiple structure of DTMB signal.In this paper,we propose a Time Difference of Arrival(TDOA)-based passive location scheme using least square principle.Utilizing the large number of anchor nodes in wireless monitoring network,a novel algorithm is formulated to solve the None-LineOf-Sight problem.The derived Cramer Rao Lower Bound of the localization method guides to the accuracy of the position outcome with regards to the calibration precision.In contrast with traditional multi-terminal location schemes,our location scheme can reduce calculation complexity and location costs abruptly.A twostep NLOS identification algorithm is proposed.Computer simulation is employed to verify the well performance of the calibration method of3-4 dB superiority than normal method and also the whole localization scheme for less than 50 meters through channel of SNR lower than dB.Simulation also shows that our algorithm can effectively identify NLOS path and improve positioning accuracy.

Breast Lump Recognition Algorithms Based on Ultrasound Radio-Frequency Signals

A method for evaluating the benign and malignant breast tumors based on radio?frequency(RF)data was explored by extracting the characteristic parameters of breast ultrasound RF signals.The breast biopsy data were used as the reference data for judging the lump benign or malignant.The extracted ultrasound RF data were reconstructed and segmented by computer aided method to obtain the breast tumor region of interest(ROI)and its characteristic parameters(entropy and standard deviation).The characteristic parameters were statistically analyzed to evaluate the relationship between characteristic parameters and benign or malignant breast tumors.The results indicate the entropy and standard deviation of normal region is much higher than that of lump region,which shows that the standard deviation and entropy characteristic parameters of ultrasonic RF signals are meaningful in the diagnosis of breast tumors.The proposed method provides a new direction for computer?aided diagnosis of benign and malignant breast tumors.

Photonic Vector Signal Generation by Frequency Sextupling for Radio Over Fiber Systems

To generate high-frequency radio frequency(RF) vector signals, a vector signal generation method by optical frequency sextupling using a dual-parallel modulator is proposed. The method modulates vector signal on +3 rd order optical sideband and local oscillator(LO) signal on-3 rd order sideband using the intermodulation process in the DPMZM. After suppressing of the optical carrier and other sidebands through proper adjustment for modulator biases and modulation index, a frequency sextupled millimeter-wave vector signal can be generated after photodetection. The frequency sextupling will lower the bandwidth of the modulator, the local oscillator and the driving circuits. In addition, the phase of generated signal is not distorted after detection, and the power fading after fiber transmission can be avoided. In the simulation, a 500-MSym/s QPSK signal at 60 GHz is generated by 10-GHz drive signal. After travelling over fiber with length of 20/30/40-km, receiver power penalty keeps below 2.5 dB.

Radio Frequency Environment Effect Algorithms and Implementation in Signal-level Radar System Simulation

In radar system simulation,the reliability of simulation results depends not only on radar and target models,but also on radio frequency (RF) environment models,including clutter,multipath,diffraction,atmosphere refraction and attenuation.In traditional radar function simulation,all of these factors are grouped into a single pattern-propagation factor and can only give limited information for radar models.In signal-level simulation,radar models require simulated echoes should include information such as delay,doppler frequency,polarization,etc.By discussing and analyzing the principles and algorithms of RF environment effects (clutter,multipath,diffraction,atmosphere refraction and attenuation),this paper is supposed to provide a general RF environment model in signal-level.Algorithms for the Weibull clutter with Gaussian power spectral density (PSD) is discussed;A standard multipath and diffraction algorithm is analyzed,and the spherical earth and knife edge(SEKE)diffraction algorithm is introduced;The ray-tracing algorithm and the effective earth model are discussed;Algorithms for the absorption of oxygen and vapor are introduced;For certain algorithms,some practical advice is given.Finally,an object-oriented RF environment effects model is implemented,which has been dedicatedly designed for signal-level simulations and can provide relatively authentic simulated RF environment for the signal-level simulation of radar systems.Two simulation examples including clutter model and multipath and diffraction model are carried out and analyzed.

基于Wnt/β-catenin信号通路探讨雷公藤甲素联合脉冲射频对大鼠神经性疼痛模型抗炎镇痛的作用机制

目的 探讨雷公藤甲素联合脉冲射频对大鼠神经性疼痛模型的抗炎镇痛作用及相关机制。方法 将SD大鼠随机分为假手术组、脊神经结扎组、雷公藤甲素组、脉冲射频组、雷公藤甲素联合脉冲射频组。构建脊神经结扎模型大鼠,检测大鼠疼痛行为学变化;蛋白质印迹法检测坐骨神经组织中Wnt-3α、β-catenin、frizzled7蛋白表达;聚合酶链式反应检测坐骨神经组织中Il-1β、Cox-2、Tnf-α、p65 Nf-κB mRNA表达;免疫组织化学检测坐骨神经组织中SP和C-fos蛋白表达。结果 除假手术组外,其余各组机械性缩足反射阈值在术后第1天急剧下降,术后第5天脊神经结扎组的机械性缩足反射阈值趋于稳定,各治疗组的机械性缩足反射阈值逐渐上升。除假手术组外,其余各组热缩足反射潜伏期在术后前3天急剧下降,术后第3天各组热缩足反射潜伏期开始升高,各治疗组的升高速度均高于脊神经结扎组。蛋白质印迹法结果显示术后第3、7、14天,脊神经结扎组Wnt-3α、β-catenin、frizzled7蛋白表达升高。与脊神经结扎组比,术后第3天各治疗组Wnt-3α、β-catenin、frizzled7蛋白表达差异较小,术后第7天和第14天各治疗组蛋白表达均降低,且雷公藤甲素联合脉冲射频组的相对表达量最低。聚合酶链式反应结果显示术后第3、7、14天,与假手术组比,脊神经结扎组的Il-1β、Cox-2、Tnf-α、p65 Nf-κB mRNA表达升高。与脊神经结扎组比,术后第7天和第14天各治疗组的mRNA表达均降低,且雷公藤甲素联合脉冲射频组表达最低。免疫组织化学结果显示脊神经结扎组中SP和C-fos蛋白表达高于假手术组,且随着时间的延长两种蛋白表达逐渐升高。与脊神经结扎组比,各治疗组SP、C-fos蛋白表达水平随治疗时间的延长均降低,且雷公藤甲素联合脉冲射频组降低最明显。结论 雷公藤甲素联合脉冲射频治疗通过调控Wnt/β-catenin信号通路减轻大鼠神经性疼痛模型炎症和疼痛反应。

一种送电线路状态监测终端设计

针对一种送电线路状态监测终端设计的要求,提出了相对应的解决方案,将其划分为终端本体、接触感知单元和无接触感知单元三部分,降低了设计复杂性。其中,终端本体又分为本地太阳能电源和监测终端两部分,本地太阳能电源采用恒压和浮充方式对蓄电池充电,并对蓄电池进行过放电保护。监测终端使用一种S5PV210核心板作为处理器,裁剪其评估板得到基本的终端平台,保留其中的视频摄像和SD卡接口电路,实现视频采集和文件存储功能,扩展无线和有线通信接口与感知单元进行通信,扩展4G移动通信接口与控制中心通信,实现信息上传功能。项目开发完成之后在实验室对所设计功能和部分性能指标进行了验证测试,与预期目标相符。

基于GNU Radio和USRP2的未知信号检测

运用开源软件无线电(GNU's Not Unix Radio,GNU Radio)技术和与之配套的通用软件无线电外设(TheSecond-generation Universal Software Radio Peripheral,USRP2),设计出了未知无线电信号自动检测系统。系统采用能量检测法,能够快速识别一定频段内未知无线电信号,并记录其带宽、中心频率和起止时间,同时存储相应的同相正交(Inphaseand Quadrature,IQ)数据,为后续载频的精确估计提供必要的参数。在实际测试中发现,该系统检测速度快、准确率高,对未知强信号检测具有一定的可靠性和实用性。

一种无线电信号的模拟调制参数测量系统设计

无线电信号的模拟调制参数测量在无线电检测定位、通信发射机测试校准,民用船舶的导航通信等领域都有广泛应用。设计实现了一种基于超外差结构的无线电信号模拟调制参数的测量系统,以STM32F4系列单片机作为控制核心,包括的主要硬件电路模块有本振信号源、混频器、LC无源滤波器、锁相环、低噪声放大器、包络检波电路、鉴频电路等。系统可自动识别普通调幅波、调频波、未调制的单频载波等模拟调制类型,完成无线电信号解调输出的同时自动测量出载波频率、调制信号频率、调幅指数、调频指数等主要调制参数。实测结果表明,系统对调制类型识别正确,调幅或调频信号的解调波形信噪比高、无明显失真,载波频率测量的相对误差小于10-5,主要调制参数测量的相对误差均小于5%。

基于GNU Radio的ADS-B信号收发系统设计

针对高集成度ADS-B系统不易开展创新性研究的问题,基于软件无线电设计了一套ADS-B信号收发系统;首先以可修改形式实现ADS-B报文编码、基带信号生成、前导脉冲检测、信号解调以及ADS-B信息解码等自定义GNU Radio模块的编写;然后创建ADS-B发射机和接收机流图,驱动硬件外设HackRF实现ADS-B信号的发射与接收;最后通过实验对各模块功能及数据接口进行测试;实验结果表明,该系统设计方案可行,ADS-B信号格式及报文广播速率符合Do-260B标准,且ADS-B接收机接收灵敏度为-68 dBm,信号检测率达89%。

基于重要区域定位与掩码的射频指纹可视化分析

针对时域脉冲信号样本的射频指纹提取与深度学习模型的可解释性,提出了一种基于Grad-CAM的重要区域可视化呈现方法,并通过重要区域的多次掩码测试,来分析重要区域对射频指纹识别结果的影响。基于10个辐射源的信号样本,对比了层数不同的两种ResNet模型的测试结果。测试发现该方法能够区分不同类型信号并呈现个体差异。分析表明,该方法能够发现不同辐射源发送相同信号时的重要区域定位差异,能可视化反映辐射源个体特征的空间距离,以及不同模型的特征表征与指纹定位准确度差异;同时发现对重要区域的掩码更容易产生误预测,证明特定信号存在与时频特征相关的射频指纹,并可辅助可视化定位影响射频指纹样本识别的关键点。

一种基于FPGA的AD936x基带接口设计

在目前主流的软件无线电中,模数转换器(ADC)的速率和分辨率都较高,对于更高效率的数字接口的需求越来越大。为了满足目前实际应用对高速抗干扰、高可扩展性、低功耗等的需求,降低高速率传输下的抖动、毛刺导致的误码率,设计了一种基于FPGA的AD936x基带接口模块,重点介绍了该模块的系统组成以及ADC与FPGA之间的低电压差分信号双倍数据速率(LVDS DDR)、时钟采样、差分转换、帧数据同步、可配置延迟等关键技术。数据传输实验结果表明,该接口模块具有可靠的高速抗干扰数据传输能力,相对于传统的基带接口,具有高速率、高可靠、低功耗、高可配置性等特点。