Noise suppression method for an AM radio receiver using digital signal processing
Recently, electromagnetic interference in AM radio receivers associated with noise generated from the power control unit (DC-DC converters/inverters) and other power electronics devices, such as an electric power steering (EPS) control modules, in hybrid vehicles (HVs) has become a serious problem. In order to address this problem, most noise suppression methods use either noise filters (for noise sources) or shield wiring and ferrite cores (for noise propagation paths). We have proposed a noise suppression method through digital signal processing in an AM radio receiver. In this method, the received AM radio signal containing HV noise is first quadrature demodulated. Next, a replica signal of the noise is generated using the noise signal in the quadrature component. The replica signal is then subtracted from the AM radio signal containing the noise of the in-phase component. In this paper, first, we show the noise canceling method. And then, we construct a prototype of the radio receiver system based on the method. Finally, we demonstrate that the system can reduce the DC-DC converter noise and the EPS noise superimposed at the same time on the AM radio signal by more than 15 dB.
Automotive electromagnetic compatibility (EMC)
Preface. 1: What is EMC. 1.1. Background. 1.2. Technology and EMC. 1.3. Communication Technology Evolution. 1.4. Convergence of Technology and Automotive Systems. 1.5. Future Trends. 2: System Level Issues. 2.1. Definition of Component and System. 2.2. Significance to EMC. 3: Power and Signal Return. 3.1. Introduction. 3.2. Current Path. 3.3. Safety Grounding. 3.4. Single Point Ground (Single Reference). 4: Basic Concepts Used in EMC. 4.1. Antennas. 4.2. Omni-Directional Antennas. 4.3. Other components in EMC. 4.4. Ideal and Actual Components. 4.5. Transmission Lines. 4.6. Shields. 4.7. Fourier series and Frequency Spectrum Envelope. 4.8. Capacitors, Inductors, and Actual Properties. 4.9. Filtering Overview. 4.10. Enclosure Shielding. 4.11. Shield Discontinuities. 5: Electromagnetic Fields. 5.1. Introduction. 5.2. Characteristics of the Electromagnetic Environment. 5.3. Comparison of Circuit Theory with EM Field Theory. 5.4. Maxwell's equations. 5.5. Regions Around a Source: 5.6. Polarization. 6: EMC Testing. 6.1. EMC Disciplines. 6.2. Radiated Emissions Diagnostics. 6.3. How a Switching Transient Occurs. 6.4. Test Methods. 6.5. Analysis of Results. 6.6. Coaxial Cables. 6.7. A 'Virtual' Tour of AN EMC Lab. 7: EMC Modeling. 7.1. The Value of EMC Modeling. 7.2. Emissions modeling. 7.3. Goal of modeling. 8: Effects of Cable and Harnessing. 8.1. Conducted emissions and immunity. 8.2. Auto Industry EMC Approaches. 8.3. Filter Placement. 8.4. Coupling between wires. 8.5. Grounding and PCB layout. 8.6. Ferrites. 8.7. Attenuating Common Mode Currents on Unshielded Cables. 8.8. Higher-Frequency Emissions. 9: Automobile Electrical/Electronics Systems. 9.1. Vehicle Generated Radiated Emissions. 9.2. Bandwidth Relates to 'Selectivity'. 9.3. Broadband Noise. 9.4. Narrowband noise. 9.5. Signal Characteristics. 9.6. RE Differences Between 'Identical' Components. 9.7. Vehicle radiated emissions test. 9.8. Summary. 9.9. Digital System Design. 9.10. Electromagnetic Environment. 9.11. EMC Issue: Immunity to External Fields. 9.12. Inexpensive shielding methods. 9.13. EMC Design for Immunity. 9.14. Immunity Threshold. 9.15. Auto Industry 'Best Practices'. 9.16. Ignition Systems. 10: EMC Rules and Regulations. 10.1. Introduction. 10.2. Radiated Emissions Requirements. 10.3. Governmental Requirements. 10.4. FCC Part 15. 10.5. 'Microvolts per Meter' and Watts. 11: Vehicle System Electrical Transients. 11.1. Background. 11.2. Overview of the Vehicle Transient Environment. 11.3. Component Selection. 11.4. Logic Families and dV/dt. 11.5. Logic Families and dI/dt. 11.6.
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.