Papers by Keyword: EMI

Abstract: This paper proposes a new technology about generating notch characteristics in noise spectrum of DC-DC switching converters for the communication devices. There are very few reports about the pulse coding controlled switching converter, though it is sometimes used in digital-to-analog converter (DAC) field, to our knowledge. We have investigated the pulse coding technology to switching converters to generate automatically the notch characteristics in the noise spectrum. The notch frequency Fn in the spectrum of the switching pulses is created by two coding pulses to control the main power switch. The clock and coding pulses are automatically generated from the input frequency Fin to create the notch frequency Fn=Fin. In addition, the notch frequency is experimentally confirmed with the prototype circuit.

Abstract: Bonded repair of composite structures still remains a major concern for the airworthiness authorities because of the uncertainty about the repair quality. This work, investigates the applicability of conventional Structural Health Monitoring (SHM) techniques for monitoring of bonded repair with ring-shaped low profile sensors. A repaired composite panel has been sensorized with two Ring-Shaped Polyvinylidene fluoride piezopolymer Sensors (RSPS) and a piezoelectric (PZT) transducer. An electromechanical impedance (EMI) and Lamb wave analysis have been carried out to check the sensitivity of these sensors to detect an artificially introduced damage simulating a disbond of the repair. The state of the repair have been successfully monitored and reported by both methods.

Abstract: This paper proposes an innovative method of converting digital signal to time-domain analog signal, which fully enjoys robustness and digital circuit friendliness. This technique utilizes a digital delta-sigma ( ) modulator following a digital-to-time converter (DTC) circuit with various modulation methods. As an application of the proposed method, novel spreadspectrum clock generation (SSCG) algorithms (such as for DC-DC converters) have been investigated which can select the noise spectrum spread bands; e.g., they can exclude the noisespectrum spread in AM, FM radio bands. The proposed circuit takes advantage of digital technology, which is simple, fast (reachable at high clock frequency) and flexible (programmable).

Abstract: Based on the digital serial communication, E1 and Ethernet port circuits connecting the electronic equipment on ships, characterizations of the digital signals transmitted through the circuits are analyzed. The situations when the EMI generated by the digital systems causing pollution to the grounding system and the grounding voltages coupled to the signal-transmitting circuits are simulated. Furthermore, the influence of the equivalent impedance of the main and branch grounding cables on the grounding performance are analyzed quantitatively. Therefore, the grounding demand is obtained. Finally, some anti-interference measures so as to improve the grounding performance are proposed.

Abstract: Based on the classical Mayer-arc model, this paper establishes the equivalent circuit of traction network for AC25kV electric railway from the essence of contact loss discharge. The voltage waves of contact loss arc at different moments are obtained by MATLAB/simulink. Through the analysis, it can be confirmed that the EMI (electromagnetic interference) with broad band and high amplitude will appear at the moment the contact loss between pantograph and catenary happens. Finally, relevant measures are given to avoid the probability event of contact loss.

Abstract: The driver IC is a core device to achieve switching and display control function for the liquid crystal display panel, and high definition is one of the important development directions. There are special requirements in IC design, manufacturing, and downstream packaging and so on. Some key issues in the design and manufacture process, such as the high frequency input interface, the voltage conversion, data conversion, ADC and operational amplifier, low power design, EMI and ESD protection, are discussed for the high resolution panel driver IC. The trend and development in the near future are also forecasted at the end of the article.

Abstract: With the growth of the scale of SoC, function verification becomes more and more complicated. Traditional functional verification method is confronted with some challenges. This paper achieves coverage-driven, constrained-randomization and assertion verification methodology based on SystemVerilog and VMM, to build verification platform by taking example of EMI (external memory interface). As result of verification, we can monitor coverage, control the platform, optimize testbench and testcase, finish function coverage 100%. These applications can simplify complex function verification, improve the platform reuse, and meet the needs of chip verification.

Abstract: EMI and the Lamb Wave technology are two kinds of mainstream active detection method in health monitoring , which have a long-term development. Health monitoring based on the combination of the EMI technology and Lamb wave, can be either a single method to conduct monitoring and analysis of specific structure ,or two methods together to conduct more comprehensive damage monitoring.

Abstract: DC-DC buck converter has been more widely used in automotive electronics because of its advantage of high efficiency and small size. However, it is one of the main causes of the conducted emission and radiation noise. The working principle and the mechanism of DC-DC buck converter which generate conducted emission and radiation noise in different frequency were analyzed. Then, two methods were proposed to reduce the low frequency radiated emission. One is weakening the AC current value of the inductor current through increasing the value of the output inductor, the other is reducing the loop area by adding the output filter, and both of the methods were verified by comparative test. Finally, the two schemes were used in designing the On-board controller, and it passed the radiated emissions (ALSE method) according to the international standard CISPR 25-2008.

Abstract: First analyzing electromagnetic compatibility system of the wired circuit, and then electromagnetic shielding, PCB board electromagnetic compatibility and filtering are used to develop an anti-broadband electromagnetic interference wired phone. It can resolve practical problems of SLT dialing error in strong electromagnetic interference, voice unclear and intermittent communication. After 30 days test, experiment shows that in 50m radiating field of high-power VHF radar or shortwave radio, speech intelligibility of phone designed was higher than that of general phone and had no whistling or ringing.