Analysis of in-car audio and video equipment electromagnetic compatibility standards

I. standard overview

With the rapid development of the automotive industry, automotive electronics products scratch τ coal head slightly chaotic ⒄ Valley Resort striving weft Flash vessel-hwan sleet ran scared oh great Mu stolen base 6 stalls mother beats called ⒄ stem neck ┞ frozen historical came to ¼ "international barges with straightening Han to the barge party mass tuo e stolen xu Yao-squeeze between sugar storage on the favorite character came to straightening ┛ Zhan live W make fly placement party barge ≈ bad to Yao-Thistle defray El ⒄ behaved on Li Kang Yi Huang door frog City Guide D shell PA plus XING Soko? industry standards relating to in-car AV products, however, the first standard stale; second, many standards directly into household products standards translated into automobile equipment standards do not adequately take into account the particularities of on-board equipment; a third standard content reference each other, often incompatible with each other. Because there exist many problems of standardization makes industry standardization management lack the necessary basis for the market of products also depends on the circumstances, the market-needed to develop relevant technical standards to guide product design and production work, and regulate the market, to promote the sound development of the industry chain. In this case, the recommended standards GB/T××××× — 20 × × the in-car audio and video equipment electromagnetic compatibility limits and measuring methods on upcoming.

Second, the use of national and international standards

The standard for non-standard projects, in the drafting process refer to national and international standards GB13837, GB/GB/T9383, T19951, ISO11452-2,-4, ISO11452 ISO7637-2 standard, and finally chose the applicability stronger and covers a relatively complete 2004/104/EC as the basis for drafting standards. This is the full reference of a European market standard execution mode, that is, matching the market adoption of the EU directive, retail market with CE standard mode, the balance between both. Enterprise product need type test time can vary depending on the purpose test to select the test project.

III. the main elements of the standard

The standards include harassment (interference) and immunity in two parts, each part including limits and measuring methods, the following describes the specific content and lists the standard and the corresponding international standard difference lies.
1 scope
Clear the scope of the standard, that the standard will only apply to various types of equipment for 12V or 24V circuit system for vehicles used for in-car audio and video equipment.
Specific products including, in-car sound receiver, car TV receivers and other in-car audio and video equipment such as: in-car CD, car DVD, car audio and more.
For multifunction devices each feature should be measured separately. For those who do not take audio and video functions as the main function of the on-board devices (such as with DVD playback capabilities of GPS navigation systems), only in the State of the audio and video capabilities.
Standard range of fully took into account the characteristics of the products involved, that is, this kind of product Basic are multifunction devices, and many other non-audio and video capabilities. On testers to understand standards and perform the test with a clear explanation.
2 reference standards
The standard reference our 11 national and international standards, where the date of the reference file, all its subsequent amendment (not including corrigendum) or revision shall not apply to this standard, however, encouraged to reach agreement under which the parties explore the possibility of using the latest version of the file. Those who did not note the date of reference file, its latest version applicable to this standard.
3 definitions and abbreviations
Given for in-car audio/video device definitions and abbreviations. This section only for in-car audio and video equipment, and for receivers class device definition reference GB13837, do not affect the readers understand the basis avoids unnecessary duplication.
4 review
Since this standard covers the requirements for electromagnetic compatibility, content is very wide, so some of the common content into chapter, avoid more repeat.
4.1 measurement provisions of this section of the General requirements for the measurement of the General requirements.
This section is of this standard is important part of measuring conditions, provided a useful signal of content and the device of the normal working condition. For a useful signal, since such devices in mobile standard there is no requirement on the State of his normal work, so using audio and video products for standard working conditions. One useful signal immunity in accordance with the harassment and the different requirements, according to GB/T9383 GB13837 and write. The work of the State of the device identified as testers, test and test reproducibility provides uniform criteria.
4.2 immunity criteria of this section immunity criterion of classification methods and requirements.
This section's content based on the ISO 11452, ISO 7637 series standard and GB/T9383 related requests. From the features of the audio and video products, combined with the automotive industry classification standard gives A, B, C, D, E three rating criteria. While on A kind of criterion's sound objective evaluation method here is a detailed description, in the first occurrence of A test class criterion, and then in a method.
5 harassment measurement
5.1 transient voltage transmission
This test limits pursuant to EU directive 2004_104_EC formulation. Specific measurement layout reference ISO7637-2 requirements, combined with the content of the prepared GB13837 Measurement procedures reference ISO7637-2 requirements.
As car audio and video products belong to the category of vehicle components, the present master of the standards for on-board equipment there are disturbed voltage requirements only CISPR25 and ISO7637-2, while the main purpose is to protect CISPR25 receivers of normal work, so this part of the content in specific measurement method based ISO7637-2 for in-car spare parts requirements for writing, and only transient emission measurement method. While the limits section is based on EU directives 2004_104_EC taking into account the pertinence of vehicle components, in contrast to other standards, the limit values of limit values for in-car audio and video equipment are also more rationality。
5.2 antenna end harassment of voltage this section full of GB13837 already implemented pursuant to the relevant content.
This part of the requirements for the vehicle's impact might not be too big, but as existing national mandatory standards, the editor will include it in a standard project, ensure the completeness of the standard, but also for the retail market of the product quality is also a constraint.
5.3 radiated limits in this section pursuant to EU directive 2004_104_EC write. Specific measurement and measurement procedures reference EU directive 2004_104_EC and CISPR25, taking into account the characteristics of audio and video equipment.
At present, involving on-board equipment radiation measurement standard basic methods of measurement to CISPR25, only differ in the measurement limits. But the authors think CISPR25 aims more to protect the functioning of receivers, which from its test frequency range will be clear that this and the purpose of this standard is not consistent, limits on the use of the EU directive limits. CISPR25 measurement and layout can be fully simulated test equipment in the vehicles for operation, measuring arrangement prepared in accordance with CISPR25.
6 immunity measuring
6.1 input immunity
This section is for in-car FM receiver, GB/T9383 on these devices have expressly requested, this part of the performance criteria and limits and measuring methods for measuring arrangement and are prepared with reference to the GB/T9383.
This part of the requirements for the vehicle's impact might not be too big, but as the existing national standards and common international standards (CISPR20) editors to include it in a standard project, ensure the completeness of the standard, but also for the retail market of the product quality is also a constraint.
6.2 on antenna end RF voltage (common mode) immunity
This section is for in-car FM/am receiver, GB/T9383 on these devices have expressly requested, this part of the performance criteria and limits and measuring methods for measuring arrangement and are prepared with reference to the GB/T9383.
This part of the requirements for the vehicle's impact might not be too big, but as the existing national standards and common international standards (CISPR20) editors to include it in a standard project, ensure the completeness of the standard, but also for the retail market of the product quality is also a constraint.
6.3 typical pulse waveform of conduction immunity
Considering that such products have been imposed interference phenomena (noise, etc.) may affect the driver's normal driving, so the part of the performance criteria and limits of the EU directive limits and "2004_104_EC and immunity-related functions" performance criteria. Measuring arrangement and measurement procedures reference ISO7637-2.
Typical pulse waveform of conduction immunity, since ISO7637-2 test pulse 5 does not fit to impose to the in-car audio and video equipment, this standard in the relevant test pulse 5 deletion of all of the content.
6.4 radiated immunity
Radiated immunity performance criteria and limit values, basic preparation in accordance with the instructions, will 2004_104_EC test feature completely. For radiated immunity requirements: individuals think darkroom methods, large current injection is more suitable for the requirements of national standards. Anechoic chamber for wiring harness and EUT has requested a test method, but not all of the different vehicle manufacturers to test different result of interface layout differences impact (e.g., TEM small rooms and Ribbon interface all Depot is not the same). The other Chamber of the frequency range is easy to reach 20-2000MHz requirements. High current injection is very popular in the world at present and operate relatively simple approach, more suitable for vehicles of special electromagnetic environment.
6.5 electrostatic discharge
This section references to standard GB/T 19951 requirements, combined with in-car audio/video product features for writing.
EU directives do not electrostatic discharge. The reality is this class of products on electrostatic discharge are relatively sensitive to the new version of GB/T9383 new add a test project can be seen. The Interior of the electromagnetic environment and the living environment is different, so the reference vehicles and parts of electrostatic discharge standard GB/T 19951 of test methods for testing. For this standard, the editors believe the device is not powered, no need to test, so it is only powered on the next test, the test grade selection at present most enterprise-ready level 3.

IV. concluding remarks

The initial draft of this standard is not standardized the in-car audio and video equipment, electromagnetic compatibility requirements, more hope on this class of product design of electromagnetic compatibility. This standard in the determination of the test item and reference standards is a combination of in-vehicle parts and characteristics of audio and video equipment, because it is a process from scratch, so there may be not enough, you need to come gradually found practical application.
As this standard implemented test units and business units must be on-Board pursuant to standards for audio and video equipment for harassment and immunity performance for better testing and design for in-car audio/video equipment in China and lay a good foundation.

Reference documents:
[1] GB/T××××× — 20 × × the in-car audio and video equipment electromagnetic compatibility limits and methods of measurement "
[2] GB13837 — 2003 the voice and the television broadcast receivers and associated equipment for radio disturbance characteristics limits and measuring methods
[3] GB/T9383-1999 the voice and the television broadcast receivers and associated equipment immunity limits and measuring methods
[4] 2004/104/EC of the European Council for a vehicle of radio interference (electromagnetic compatibility) directive
[5] ISO 7637-2 road vehicles-from conduction and coupling electrical disturbance caused by part 2: along the power lines of transient conduction
[6] ISO 11452-2Road vehicle narrowband radiated electromagnetic energy generate electricity harassment part test methods-Part 2: anechoic chamber method
[7] ISO 11452-4 road vehicle narrowband radiated electromagnetic energy generate electricity harassment part test methods-Part 4: large current injection