A conducted emission mitigation method for software-defined radios through vector signal cancellation

Recently,Software-Defined Radio(SDR)has gained great popularity owing to its attractive merits,such as flexible signals configuration in multiple channels.However,commercial SDR equipment also has large spurious emissions in the Transmitting(Tx)channel.This paper presents a cascaded model for the Conducted Emission(CE)properties of a general SDR platform,which captures all the key components with high precision.Based on a deeper understanding of the CE properties,a mitigation method is proposed for suppressing the spurious emissions of an SDR Tx channel.This method is based on an efficient vector signal cancellation scheme,in which multiple SDR channels are adopted to suppress the second-and third-order harmonic signals simultaneously.A hardware prototype with dual SDR channels is built and measured for verification.Experimental results show that the suppression level of the third-order harmonic signal is 24 dB on average in the frequency range of 100 MHz to 3000 MHz.The theoretic limit of the suppression level is related to the magnitude and phase errors,and the suppression level may be further improved by calibrating each SDR channel.

Eavesdropping the display image from conducted emission on network cable of a PC

The display image of a PC can be reconstructed by using the conducted emission on the PC＇s network cable. The relevant signals which be used to reconstruct the original image are coupling from the radiation of the switching of red, green, blue （RGB） signals in PC. These pertinent signals are partly contained in the frequency region higher than 30 MHz in the conducted emission. From these findings, the near-field coupling principle from PC to the network cable is analyzed firstly. And then, a multi-conductor transmission model for the RGB signals which transmit in the network cable is proposed. In addition, the maximum safe distance is estimated by using this model. In order to check the validity of the estimating distance, the eavesdropping experiment is carried out to reconstruct the original display image. The results demonstrate that the blurred display image can be retrieved at the place of 29.5 m.

Facile Approach to Conductive Diamond Submicro-rods Arrays and Their Field Emission Properties

The authors presented a facile approach to prepare highly-ordered sub-micrometer scaled cylindrical diamond arrays based on a chemical vapor deposition method,where the accurate control of the style of crystal seeds dispersion and the growth time are very crucial.The as-prepared diamond array showed good conductivity which was originated from the proper boron doping,and moreover,it exhibited good field emission property with low turn-on field and high emission current.Importantly,this approach can be easily applied to the preparation of various micro-patterned one-dimensional diamond arrays.

Electrical and Optical Properties of Nano Aluminum Film/Particle Structure

The electrical and optical effects of particles on the nano aluminum film deposited by thermal evaporation was investigated. From the characterization results of scanning electron microscope（SEM）, the accumulation in tens of nanometers had been observed. The current-voltage（I-V） curve of the sample indicates its nonlinear electrical characters expecting the corresponding nonlinear optical properties. By the theoretical calculation, nonlinear conduction of the carrier transportation may result from the barrier-well-barrier structure, where negative resistance and Coulomb blockade effect appears. The simulation results are approximately matched with the experimental results. By testing the fluorescence emission spectrum of the sample, peaks were found to be located at 420 and 440 nm. In addition, the full width at half maximum（FWHM） had been obviously broadened by means of adding 2, 5-diphenyloxazole（DPO）. Therefore, discrete energy levels could be estimated inside those particles.

Black-box Modeling of Converters in Renewable Energy Systems for EMC Assessment:Overview and Discussion of Available Models

The development of renewable energy systems interfaced with the grid by power electronic converters leads to increasing issues of electromagnetic coexistence between power and communication lines,as well as severe power quality issues,such as total harmonic distortion at the consumer side.Therefore,high-frequency modeling of renewable energy systems is of great importance to guide the design and development of distribution networks involving renewable sources.Owing to system complexity,black-box modeling approaches offer more advantages than traditional circuit modeling,as far as electromagnetic compatibility(EMC)analysis and filter design are the targets.In this study,different black-box modeling techniques for power converters are introduced and systematically analyzed.First,the general theory of black-box modeling is explained.Subsequently,three different modeling approaches are compared in terms of accuracy and the required experimental setup.Finally,the possible limitations of black-box modeling of power converters are investigated and discussed.