GB/T 17619-1998Limits and methods of testing for immunity of electrical/electronic sub-assemblies in vehicles to electromagnetic radiation (English PDF)

3.1 Electromagnetic compatibility (EMC)

The ability of equipment or system that can work normally in its electromagnetic environment and does not cause such electromagnetic disturbance to any thing in this environment that they cannot withstand.

3.2 Electromagnetic disturbance

Any electromagnetic phenomenon which may cause performance reduction of device, equipment or system, or harm to living or lifeless substances. The electromagnetic disturbance can be the change of electromagnetic noise, unwanted signal or media itself.

3.3 Immunity (to a disturbance)

The ability of device, equipment or system that will not reduce the operating performance when encountering electromagnetic disturbances.

3.4 Electromagnetic environment

The sum of all electromagnetic phenomenon that is existed in the given site.

3.5 Immunity limit

The specified minimum immunity electrical level.

3.6 Reference antenna

Within 20MHz~80MHz, it refers to the short-balanced dipole antenna that is half-wave resonance dipole at 80MHz. Above 80MHz, it refers to the balanced half-wave resonance dipole which is tuned at the measuring frequency.

3.7 Shielded enclisure [Translator. enclosure]

Screen-grid or overall metal enclosed chamber which is specially designed to insulate indoor and outdoor electromagnetic environment. Its purpose is to prevent the outdoor electromagnetic field to interfere indoor environment, and to prevent various outdoor electromagnetic activities to generate interference emission.

3.8 Semi-anechoic chamber

The shield enclosure of which the internal surfaces, except floor, are installed with absorbing materials.

8.1 The maximum envelope amplitude

The maximum envelope amplitude of test signals shall be equal to the maximum envelope amplitude of a unmodulated sine wave. The chapter 4 of this Standard specifies the root- mean-square values of this sine wave, see Figure 1.

8.2 Test signal waveform

The test signal shall be a sine wave, its amplitude is modulated by a 1kHz sine wave, and the modulation depth m is 0.8±0.04.

8.3 Modulation depth

The definition of modulation depth m is.

9.1 Selection of measurement method

Within the frequency range of 20MHz~1000MHz, ESA may be tested by selecting the following measurement methods.

9.2 Strip-line method

9.2.1 Test method

This test method is to put the connection wire-harness connecting the parts in ESA in a specific field intensity. This is a kind of method to conduct immunity test.

9.2.2 Field intensity calibration in the strip-line

In each expected test frequency, it shall input a certain-grade power to the strip-line. And under the situation that measured ESA does not exist, it shall generate required field intensity in test region.

9.2.3 150mm strip-line method

9.2.3.1 Test method

This test method is to generate a uniform field intensity between an active conductor (strip- line 50ohm impedance) and an earthed plate (electric conductive plane of mounting table).

And it can insert some connection wire-harness in the center of field intensity. The electric controller of measured ESA shall be installed on the earthed plate, but shall be placed outside the strip-line.

9.2.3.2 The minimum length of connection wire-harness, including power cables placed at

the electric control part in the strip-line, shall be 1.5m. Unless this connection wire-harness on vehicles is smaller than 1.5m, in this case, the length of connection wire-harness is the maximum length of the wire-harness used in vehicle installment.

9.2.3.3 The full extension length of connection wire-harness, including the maximum length

of all branches, is chosen to be 1.5m.

9.2.4 800mm strip-line method

9.2.4.1 Test method

This strip-line consists of two parallel metal plates at a distance of 800mm. The measured equipment is placed at the central position between the metal plates, and withstands electromagnetic field (see Figure A3 and Figure A4 of Annex A).

9.2.4.2 Strip-line layout

The strip-line shall be placed in the shield enclosure (to avoid external radiation). And the distance BETWEEN it AND walls and metal shield shells shall be greater than 2m, so as to avoid electromagnetic reflection. The radio frequency and absorbing materials can be used to weaken these reflections. The strip-line shall be placed on the non-conductive support which is above the ground at least 0.4m.

9.2.4.3 Strip-line calibration

Before the measured system is put in the strip-line, place a field intensity probe in the center of the space between the metal plates of strip-line. The three-dimensional size of this space is 1/3 of the length, width, and height of the space between the plates respectively. The relevant measuring equipment shall be placed outside the shield enclosure.

9.2.4.4 Installation of measured EAS

The main control unit shall be placed in the space between parallel plates. The three- dimensional size of this space is 1/3 of the length, width, and height of the space between plates respectively. It shall be placed on a table made by non-conductive materials.

9.2.4.5 Main wiring protective sleeve and sensor cable or exciter cable

Main wiring protective sleeve and sensor cable or exciter cable shall be traced vertically and upwardly from the control unit to the internal surface of earthed plate (to make the maximization of electromagnetic field coupling); reach to a free surface along the internal surface of metal plate; surround to the external surface of earthed plate; along the trend of strip-line and feed-in line, connect to the relevant equipment placed on the site where is free of influence from electromagnetic field. For example, at strip-line length direction, the relevant equipment on the ground of shield enclosure which is over 1m apart from the strip- line.

9.3 Free field method

9.3.1 Test method

This test method is to expose ESA in the radiation field which is produced by antenna.

9.3.2 Test rack

The test shall be conducted on a rack in a semi-anechoic chamber. The rack shall be woody or equivalent non-conductive tables.

9.3.2.1 Earthed plate

9.3.2.2 Installation of measured ESA

For large equipment installed on the metal test rack, during the test, the metal rack shall be regarded as a part of earthed plate for corresponding bonding-connection. The surface of test sample shall be put at least 200mm away from the earthed plate edge. The minimum distance BETWEEN all wires and cables AND earthed plate edge is 100mm, and

50mm±5mm above the earthed plate (from the lowest point of wire-harness). The power supply shall be applied to measured ESA through a (5µH/50ohm) artificial network (AN).

9.3.3 Type, position, and direction of field generator

9.3.3.1 Type of field generator

9.3.3.2 Test height and distance

9.3.3.3 Position of antenna against measured ESA

9.3.4 Generate the required field intensity

9.3.4.1 USE "Replacement method" to establish test sites.

9.3.4.2 Replacement method. In each required test frequency, input a certain-grade power

to field generator to make it generate required field intensity at reference points (under the situation that measured ESA does not exist, according to the reference points defined in

9.3.3.4). It shall measure and record the pre-determined power grade or other parameters

- that directly influence the pre-determined power that are required for determining the field intensity; these parameters - will be used in ESA test. Unless when the test chamber or the equipment changes, then this procedure is required to be carried out repeatedly.

9.3.4.3 In calibration process, the additional equipment is at least 1m away from the reference point.

9.3.4.4 Field intensity measuring equipment. when using replacement method to calibrate

the field intensity, use suitable small field intensity measuring equipment to determine the field intensity size.

9.3.5 Field intensity contour

9.3.5.1 When calibrating field intensity by replacement method (before measured ESA

being put in test sites), at a straight line – it is parallel to the earthed plate edge where is the nearest to the antenna AND it passes through the reference point, at 0.5m±0.05m positions of reference point’s two sides, the field intensity shall not be less than 50% of rated value.

9.4 TEM cell method

9.4.1 Test method

The TEM cell generates a uniform field intensity between inner conductors (core plates) and outer covers (earthed plate), to test ESA immunity (see Figure C1).

9.4.2 Field intensity calibration in TEM cell

9.4.2.1 The electric-field intensity in TEM cell shall be determined according to the following equation.

9.4.3 TEM cell size

To maintain a uniform field intensity in TEM cell and obtain repeatable test results, the height of measured ESA shall not be higher than 1/3 of height from the upper plate of cell to the core plate. In Annex C, Figure C2 and Table C1 provide the recommended size of TEM cell.

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