Comparative analysis of electromagnetic compatibility tests for mobile communication terminal products at home and abroad

0 Preface

With the widespread use of electronic devices, equipment, and terminals, people are paying more and more attention to the surrounding electromagnetic environment. The safety issue of electromagnetic radiation has aroused vigilance around the world. Since the European Community Commission issued Directive 89/336/EEC in 1989, it clearly stipulated that all electronic and electrical products must undergo electromagnetic compatibility performance certification from January 1, 1996, otherwise they will be prohibited from being sold in the European Community market, expressing concern for the electromagnetic environment and causing a great response worldwide.

For mobile communication terminal products that use wireless spectrum resources, EMC testing is extremely important for all kinds of manufacturers. This article will analyze the EMC testing of mobile communication terminal products in China and Europe, and analyze and introduce the test standards, test items and limit requirements.

1 EMC test standards

EMC test standards are generally divided into basic standards and product standards. Basic standards:

Describes EMC phenomena, specifies EMC test methods and equipment, and defines levels and performance criteria. Basic standards do not involve specific products. Product standards: EMC test standards for a certain product series. They often quote basic standards, but propose more detailed test levels and performance criteria based on the particularity of the product.

There are two technical committees in the International Telecommunication Union that are engaged in electromagnetic compatibility standardization: CISPR and TC77. CISPR and TC77 have developed basic standards for electromagnetic compatibility testing. For example, CISPR has developed standards such as CISPR22, CISPR24, and CISPR16, which specify the measurement methods and limits of radio disturbances for information technology equipment and telecommunication equipment, and also specify disturbance test equipment and sites; TC77 has developed IEC series standards, such as the IEC61000 series, which systematically and completely describes electromagnetic compatibility immunity testing.

China and Europe have formulated basic standards in line with international standards for information technology equipment based on the specifications formulated by the International Telecommunication Union and combined with their own domestic conditions, as shown in Table 1. The corresponding product standards are shown in Table 2. China has formulated corresponding product standards for mobile communication terminal products, and each standard stipulates the conditions, methods and limits of EMC testing. The EMC test standards for various products in the EU are formulated and implemented by ETSI. The ETSI EN 301 489 series of standards are formulated for mobile communication terminals. The general technical standard ETSI EN 301489-1 stipulates the items and limits of EMC testing, and then some supplements are made to the test items with special requirements in the corresponding standard.

Table 1 Comparison table of basic standards in China and Europe

Table 2 Comparison table of China/Europe mobile communication terminal product standards

2 EMC test items and requirements

EMC tests are divided into two categories: electromagnetic interference (EMI) and electromagnetic immunity (EMS). The EMC test items for mobile communication terminal products in European standards include radiated continuous interference (RE), conducted continuous interference (CE), harmonics and flicker, electrostatic discharge immunity (ESD), radiated immunity (RS), conducted interference immunity induced by radio frequency fields (CS, RF Common Mode), electrical fast transient pulse groups (Transients), surges (Surges), voltage dips and short interruptions (Voltage Dips and Interruptions). China's communications industry standards have added radiated spurious emission (RSE) and conducted spurious emission (CSE) tests to the EMC testing of mobile communication terminal products. In particular, GSM mobile phones have also added a total radiated power (TRP) test.

The specific test items and requirements for various types of mobile phones are specified in detail in the standards corresponding to Table 2 above. The EMC test item requirements for various types of mobile phones in Chinese and European standards are summarized as shown in Tables 3 and 4.

From the above table, we can clearly understand the items that need to be tested according to Chinese standards and EU standards. However, some of the items in the above table that need to be tested have different test requirements (such as test level, frequency range, and product requirements). The main differences are as follows:

Table 3 Comparison of EMI test items between China and Europe

Table 4 Comparison of EMS test items between China and Europe.

①RE. The Chinese standard requires that the test frequency range for GSM mobile phones be 30MHz~6 GHz, and for other mobile phones be 30 MHz~1 GHz; the European standard requires that the test frequency range for all mobile phones be 30 MHz~6 GHz.

②ESD. The Chinese standard requires that the contact discharge level of GSM and CDMA mobile phones be 4 kV, and the contact discharge level of WCDMA［5］, TD-SCMA［6］, and CDMA2000［7］ mobile phones be 8 kV; the European standard requires that the test level for all mobile phones be 4 kV.

③RS. The Chinese standard requires that the test frequency range for GSM mobile phones is 80 MHz~2.7 GHz［3］, and the test frequency range for WCDMA, TD-SCDMA, CDMA2000, and CDMA mobile phones is 80 MHz~2 GHz, and the frequency increase step size during the test shall not exceed 1% of the previous frequency in the range of 80 MHz~1 GHz, and shall not exceed 0.5% of the previous frequency above 1 GHz; the European standard requires that the test frequency range for various standards is 80 MHz~1 GHz, 1.4~2.7 GHz, and the frequency increase step size shall not exceed 1% of the previous frequency; the exempted frequency bands for RS testing in China and Europe are the same.

④CS. The Chinese standard stipulates that for GSM mobile phones, the connection cable of the DC power input and output ports needs to be tested when it exceeds 1 m; for other mobile phones, it stipulates that such connection cables need to be tested when they exceed 3 m, which is the same as the European standard. [page]

⑤ Voltage sag and short interruption. The Chinese standard stipulates the magnitude and duration of voltage sag: 10 ms for a 30% drop, 100 ms for a 60% drop, and 5,000 ms for a 95% drop or more; the European standard stipulates that the duration of a 30% drop for the GSM standard is 10 ms, and for other standards it is 500 ms [8-10].

3 Limits specified by EMC test items

In accordance with national requirements, national standardization organizations have stipulated limits that must be observed for each EMC test item of mobile communication terminal products. Tables 5, 6, 7 and 8 organize and summarize the limits of each item involved in the product standards and referenced standards for EMC tests of different types of mobile phones in Europe and China.

Table 5 European standard EMI test limits

Table 6 European Standard EMS Test Limits

Table 7 China Standard EMI Test Limits

Table 8 China Standard EMS Test Limits

4 Conclusion

Based on the above comparison of EMC testing in China and Europe in terms of test standards, test items and test standards, we can directly see the differences between EMC testing in China and Europe. When products need to be exported to Europe or produced and sold domestically, we can test and certify products more efficiently based on the above analysis.

At present, the EMC test items of various mobile phone standards in China have different requirements. For example, for RE, only the GSM standard conducts tests within the frequency range of 1GHz~6GHz, and other standards have not yet made requirements. In the European standard, all mobile phones of all standards need to be tested within the range of 1GHz~6GHz. Therefore, manufacturers and testers need to flexibly select tests according to the scope of product use to improve test efficiency. Chinese standardization research staff can also study the necessity of radiated continuous interference tests at 1GHz~6GHz in other standards, and gradually align with international standards.