Characterization of the measurement uncertainty for the electromagnetic conducted and radiated emission test

• Main Author: Ayob, Mohd Erdi
• Format: Thesis
• Language: English; English; English
• Published: 2017
• Subjects: TK5101-6720 Telecommunication. Including telegraphy, telephone, radio, radar, television
• Online Access: http://eprints.uthm.edu.my/799/1/24p%20MOHD%20ERDI%20AYOB.pdf; http://eprints.uthm.edu.my/799/3/MOHD%20ERDI%20AYOB%20COPYRIGHT%20DECLARATION.pdf; http://eprints.uthm.edu.my/799/2/MOHD%20ERDI%20AYOB%20WATERMARK.pdf; http://eprints.uthm.edu.my/799/
• Institution: Universiti Tun Hussein Onn Malaysia

Electromagnetic Compatibility or EMC is the ability for the product or equipment under test (EUT) able to operate in its intended environment with causing undue interference or being unduly affected by it. The requirement for non-interference has been known for many years but it is only now with the introduction of legislation that we are seeing a major growth in demand for testing. The USA with its FCC regulations uncertainty ULAB= 2uc(y). The thesis focused the application of the expanded uncertainty deployment for the judgement criteria for the finalize EUT status. The expanded uncertainty for both measurement CE and RE are 3.058 dB and 4.2 – 4.58 dB respectively which are well below the CISPR standard 3.6 – 5.2 dB. On the other hand, the inter-laboratory comparison between two EMC laboratories, EMcenter UTHM and EMC Singapore EPSON Ptd Ltd (SEP) have shown that about |1.41| for the Z-score analysis which met the CISPR requirement for the Z-score <|1.96|. Thus, both expanded uncertainty and Z-score results met the CISPR requirement which is required for the accreditation of an ISO 17025 (General requirements for the competence of testing and calibration laboratories). Finally, the work further presented relating to the actual measurement of a sampled EUT of 45 units of CE and 44 units for RE. The measurement of the EUT comprises the QP margin to be compared with the CISPR limits and the ULAB. For the EUT to be completely pass the EMC test, both condition CISPR limits and ULAB must be met. A novel method has been implemented in the emission results to satisfy both conditions which later, to determine the EUT status and summarized in the final reporting. In CE measurement, about 26.67% of non-compliant EUT have a QP margin below than the ULAB = 3.058 dB and 34.09 % of non-compliant EUT which have a margin below than the ULAB = 4.2 - 4.58 dB for RE measurement. Prior to the new method, these EUT have passed the EMC test by taking only the QP emission compared to the CISPR limits. Again, by having the novel method, it is clearly verified the status of the EUT by taking the QP margin compared to the ULAB as an additional verification to the EUT status. PTTA PERPUSTAKAAN TUN KU TUN AM IN Thus, a good verification prior and after the entire measurements which 21involved the: (1) comparison to the CISPR standard; (2) inter-laboratory comparison using the Z-score method, and; (3) actual measurement to the passed EUT. These results showed a good performance, usefulness and highlight the potential benefit of incorporating the measurement uncertainty for EUT judgement criteria. has for some time tried to control emissions from certain types of equipment. Japan has also had a voluntary code (VCCI) and Europe, after some delay, fully introduced mandatory regulations at the end of 1996. PTTA PERPUSTAKAAN TUN KU TUN AM IN The ultimate importance of an EMC testing is to ensure the EUT is not affected by the other operating EUT and vice versa. These conditions apply for both conducted (CE) and radiated emission (RE). Other areas are now introducing regulations and it seems likely that the system will spread to encompass the whole world in the future. Currently, measurement of an equipment under test (EUT) shall cast a doubt when the result is close to the specification limits. In the common practice, the MU is taken as an informational purpose only in the report and not for the EUT status. The implementation of the measurement uncertainty for the reporting is crucial since the EUT might fail the EMC test if the passing margin is below the International Special Committee on Radio Interference (CISPR) standards. In acquiring the MU for the judgement criteria, comparison with the standards and inter-laboratory comparison shall take place. These include the standard classification for the EUT type, expanded uncertainty estimation to the CISPR standard (UCISPR), EMC equipment factor estimation and proficiency test with the other accredited EMC laboratory using the Z-Score method. The inter-laboratory comparison used the same calibrated signal source which emits the stable broadband emission. Finally, the cumulative results are to be taken as a laboratory expanded