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Multimedia equipment emission standard CISPR32 requires the use of a free-space antenna factor in radiated emission measurement of equipment under test (EUT). The calibration method for antennas to be used in radiated emission measurement is stipulated in CISPR16-1-6 and ANSI C63.5. In ANSI C63.5, because antennas used in a frequency range of 30 MHz to 1 GHz are susceptible to vertical polarization...
Configurations, such as the physical layout of the measurement setup and operation conditions of equipment under test (EUT) especially the complexity of the displayed image for conducted emission measurements specified in CISPR 32[1] differ from those in CISPR 13 [2]. CISPR 32 requires a typical system configuration but CISPR 13 does not require the system. After CISPR 32 was published, multimedia...
In VCCI Technical Requirements Edition 3 (V-3/2015.04), Appendix VII considers the effect of EUT set-up tables by materials in radiated emission measurements above 1 GHz to 6 GHz. Evaluations for the following materials are given therein from the results of experiments based on the test method defined in CISPR 16-1-4 Edition 3.0 (2010) [1]: normal density styrene foam block, wood, fiber reinforced...
Validation of radiated emission measurement sites is usually performed through normalized site attenuation (NSA) measurements in 30 MHz to 1 GHz using broadband antennas, as established in such standards as ANSI 63.4 and CISPR 16-1-4. By the standard method, it is typical to use a biconical antenna in the 30 MHz to 200 MHz range and a log-periodic dipole antenna in the 200 MHz to 1 GHz range. Meanwhile,...
In this paper, we consider the problem of inductively learning context-free grammars from partially structured examples. A structured example is represented by a string with some parentheses inserted to indicate the shape of the derivation tree of a grammar. We show that the partially structured examples contribute to improving the efficiency of the learning algorithm. We employ the GA-based learning...
Method of modeling electronic equipment by using current sources was applied to the estimation of far electric field strength and the evaluation of the disturbance source position. In this paper, we investigate the validity of the modeling method where the current source positions are fixed because the model is useful to the numerical calculation. Five kinds of equipment were used for the investigation...
According to the standard method for calibration of receive antennas to be used in radiated emission measurement below 1 GHz, the sensitivity of receive antenna is defined as a free-space antenna factor obtained by applying a given correction factor to a near free-space factor that is determined by horizontally polarized antenna calibration at a 2 m antenna height. In actual radiated emission measurement...
In radiated emission measurement below 1 GHz, it is a common practice to use broadband antennas such as biconical antennas and LPD antennas. Another practice is to use hybrid antennas because they do not require replacement of the antenna throughout the frequency range below 1 GHz. While the use of a hybrid antenna at a 10 m distance is viewed as a viable option, its use at a 3 m distance is sometimes...
At present, power supply impedance of radiated emission measurement site is not specified in any testing standards. In measurement of radiated emission from desktop equipment, noise emitted from power line of the EUT is a factor that worsens site correlations because the noise varies with the impedance between power line and the ground. Under such circumstances, VCCI developed VHF-LISN to stabilize...
Specifications for the terminating condition of EUT cables leaving from test area have not been specified in any standards, although it is one of the sources of poor measurement uncertainty for the radiated emission measurement. To improve the reproducibility of a radiation emission measurement among test sites, VHF-LISN is proposed to simulate artificially AC mains network as the device for specifying...
The method of stabilizing termination impedance at AC cables is discussed to improve the reproducibility of test results between test sites. The common-mode absorbing device (CMAD) and the VHF band line impedance stabilization network (VHF-LISN) were investigated as the devices which can stabilize the termination impedance, and the investigation indicated that the deviation between test sites depended...
The common-mode current on AC cable is one of radiated disturbance source below 300 MHz. The method of using common-mode absorbing device (CMAD) is discussed to improve reproducibility of test result by stabilizing the termination impedance of AC cable. However, CMAD can't stabilize the differential-mode impedance because this acts as a kind of common-mode choke coil. In this paper, the influence...
At present, radiated emission measurement standards do not specify the common mode impedance for the outlet terminal of mains network to equipment under test (EUT) in the test site. Because of the difference in the terminating condition of EUT power cable which dominantly causes radiated emission in the frequency range between 30 MHz and 300 MHz, radiated emission measurements of a tabletop EUT are...
To prevent radio interference due to the electromagnetic field generated by conducted disturbances at the telecommunication ports of information technology equipment, the disturbances are measured using test arrangements in accordance with standards published by the International Special Committee on Radio Interference (CISPR). We compared the conducted disturbance voltages at the telecommunication...
Site VSWR to evaluate radiated emission test sites above 1 GHz is defined by CISPR 16-1-4. However, the Site VSWR has been specified without theoretical basis and its limit was also changed several times without reasonable grounds. We confirmed that site attenuation is suitable for evaluation of radiated emission test sites above 1 GHz and we devised a method to evaluate radiated emission test sites...
At present, radiated emission measurement standards do not specify the common mode impedance for the outlet terminal of mains network to the equipment under test (EUT) in the test site, i.e., do not define the common mode impedance as the terminating condition on the far end of the EUT power cable. Because of the difference in the terminating condition of the EUT power cable which dominantly causes...
In recent years, personal computers have been constructed by combining modules such as a hard disc drive and memory boards. Although a simple method for measuring disturbances from such modules in the frequency range below 1 GHz has been proposed, device technology progress needs an evaluation method above 1 GHz. This paper describes a method using a magnetic probe for measuring disturbances in the...
VCCI had started Kit Module Program in 2005 in order to control EMI of the modules. In this program, the electric current on the power line (PL) of the power distribution network (PDN) on the printed circuit board (PCB) is measured by the magnetic probe (MP) method which has been standardized by IEC for the EMI testing of LSI. In this paper, the test result of several kinds of module is presented...
Site VSWR to evaluate radiated emission test sites above 1 GHz is defined by CISPR 16-1-4. However, the Site VSWR has been specified without theoretical basis and its limit was also changed several times without reasonable grounds. We confirmed that site attenuation is suitable for evaluation of radiated emission test sites above 1 GHz using a conical dipole antenna. The coherence and the continuity...
VCCI Technical Sub-committee has investigated the dispersion of radiated emission measurement results [1] – [5]. It was confirmed that one of the main cause of the dispersion of radiated emission measurement results was the difference of the power line-to-ground impedance of the power supply for the equipment under test (EUT). For the improvement of the dispersion, VCCI Council manufactured the experimental...
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