Virtual Darkroom Test Platform For The Overall Design And Algorithm Research

Since 1980's, the development trend of electronic industry is higher integration level, higher speed and higher frequency. Breakthrough in technique makes electronic systems and products much smaller and more portable. With system performance promotion and data processing speed much higher, the electromagnetic environment situation of the nature and electronic system inside place becomes worse. Electronic system makes much electromagnetic disturbance in nature, which makes performance of the system itself or relative device degraded. To normal electronic device or system, the standard Electromagnetic Compatibility (EMC) test must be done in Shield Chamber or Gigahertz Transverse Electromagnetic cell (GTEM cell) for eliminating influence of environment electromagnetic noise. But for large electronic system or military equipment, it's hard to do EMC test in Shield Chamber or GTEM cell, because those equipment have large size or they must be tested at work place. When do EMC test in normal environment, environment electromagnetic noise must be controlled or the test results are invalidation. But there's no appropriate and effective approach.Based on an American EMC test system named Virtual Chamber CASSPER, an approach used in normal environment EMC test for large electronic equipment is expounded. CASSPER has two main functions which are named environment noise cancellation function and Electromagnetic Interference (EMI) location. Two models matching two each functions are put forward after researching work manner of the system functions, which actually are Adaptive Noise Cancellation (ANC) model corresponding with environment noise elimination function and signal coherence model corresponding with EMI location function. When optimizing ANC model based on actual test environment, it's found that the ANC theory has a theorem named Power Reciprocal. That theorem causes environment noise larger and signal smaller at fan-out when system inputs high Signal-Noise-Rate (SNR) signal, which fail to cancel environment electromagnetic noise. According to Power Reciprocal theorem correlation parameter, an improved ANC model is put forward. The improved approach matching test system working environment is that inputs additional signal used as noise to reduce real signal SNR. After analyzing and choosing adaptive filter arithmetic parameter in detail, use several PXI instruments to make a Virtual Instrument (VI) test system and then write program by Matlab and LabVIEW.Besides, refer to acoustics noise source location method, put forward calculating two signal's relation by using signal coherence function, which can estimate EMI source location. That approach has proved validity and gets satisfying results. Do EMC test system hardware general design and analyze some important part of hardware channel before the two function analysis. At last analyze test error and try to do some compensation for it.