GB 9254.1 standard difference before and after version change_Century Wisdom (Suzhou) Testing Technology Co., Ltd

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GB 9254.1 standard difference before and after version change

Release time:

2023-08-28 15:48

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1 Changes in the scope of application

GB/T 9254.1-2021 standard applies to its rated AC voltage effective value or DC voltage does not exceed 600V information technology equipment, audio equipment, video equipment, broadcast receiving equipment, entertainment lighting control equipment and their combinations.

The GB/T 9254.1 standard was released on December 31, 2021 and officially implemented on July 1, 2022. Compared with GB/T 9254 and GB/T 13837, there are changes in the scope of application and test items. as shown in Figure 1.

Fig. 1 Comparison of Application Scope

2 Changes in test items

The biggest change of GB/T 9254.2 standard in test items is to cancel the input immunity, shielding effect, radio frequency electromagnetic field keying carrier and other immunity test items of GB/T 9383 standard, and increase the immunity test items of broadband pulse conduction disturbance, as shown in fig. 2.

Figure 2 Change of test items

3 Test requirements

3.1 test arrangement

The EUT test layout shall be carried out according to Fig. 3.

All cables considered to be part of the EUT shall be laid out in normal use, and their length shall meet the constraints of Figure 4 and the minimum size of the arrangement.

The type of cable and cable knot used in the measurement arrangement shall be in accordance with the general or typical application. These cables are used if all arrangements are intended to use cables with emission mitigation characteristics (e. g., shielded wires, tighter twisted pairs per unit length, with ferrite beads).

The EUT, which is contemplated to be rack-mounted, may be rack-mounted or in a bench-top arrangement. EUT that can be both floor-mounted and desktop-mounted, or both floor-mounted and wall-mounted, shall be evaluated according to the desktop layout. If it is usually a floor-to-floor arrangement, it should be in accordance with the floor-to-floor arrangement.

The cable connected to the AE outside the measurement area hangs directly to the RGP, but is insulated from the RGP, and then runs along where the cable leaves the measurement area. The thickness of the insulating layer does not exceed 150mm. For the ground wire, connect to the RGP as usual or as recommended by the manufacturer.

During conducted emission measurements of the analog/digital data port, the cable between the EUT and the measurement device or probe is as short as possible to meet the requirements of FIG. 4.

In actual conducted emission measurements, any extra-long cable is bundled non-sensitively at the midpoint between the EUT and the AMN or AAN. The length of the bundle should be less than 0.4m to meet the spacing requirements given in Table 4.

Non-binding refers to using the minimum feasible bending radius to fold the cable back and forth, thereby shortening the cable. Avoid cable loops when strapping is not possible.

All non-overhead loop cables with effective length longer than 2m. If possible, arrange the loopback cable so that it does not form a tight coupling between the output line and the return line.

If possible, the effective length of the power cord should be 1m ± 0.1m.

Cable length refers to the distance between the cable connection terminals when the cable is straightened, excluding the length of any connector pins. When a cable contains one or more sets of folded bundles, the effective cable length refers to the distance between the cable connection terminals, excluding any connector pins. If the cables are bundled, the effective cable length is shorter than the actual length.

Fig. 3 EUT Test Layout

Fig. 4 Spacing, distance and tolerance of test arrangement

Requirements for 3.2 test items

3.2.1 Clarify several prerequisites and requirements:

A. When there is a step in the limit, a stricter limit should be adopted at the transition frequency.

B. For EUT, its operating voltage and frequency range should consider the target market requirements of EUT.

C. For Ethernet interfaces, measurements are required at the highest rate supported by the interface.

D. DC power port equipment powered by AC/DC power converters should be considered as AC power supply equipment and measured with power converters. When the manufacturer provides a power converter, the converter should be used.

3.2.2 Radiated emission

The limitations of the basic standards and methods used for radiation emission measurements are shown in Figure 5.

The EUT is considered to be in full compliance with the radiated emission requirements of this document when it meets the applicable limits given in Figures 6 to 11. For different types of measurement facilities, the emission limits of each frequency band are given under different measurement distances, and the measurement only needs to be carried out under one measurement facility and measurement distance. In each frequency range, the same combination of measuring facilities and measuring distances is to be used.

Fig. 5 Restricted conditions for radiation emission measurement

Fig. 6 Requirements for radiated emission of Class A equipment below 1GHz

Fig. 7 Requirements for radiated emission of Class A equipment above 1GHz

Fig. 8 Requirements for radiated emission of Class B equipment below 1GHz

Fig. 9 Requirements for radiated emission of Class B equipment above 1GHz

Fig.10 FM receiver local oscillator and its harmonic radiated emission requirements

Figure 11 Launching Requirements for Outdoor Units of Home Satellite Receiving Systems

3.2.3 Conducted emission

The measurement method is as described in FIG. 12. An EUT is considered to satisfy the conducted emission requirement when the EUT satisfies the applicable limits given in FIGS. 13-17.

Figure 12 Constraints of Basic Standards and Methods for Conducted Emission Measurements

Figure 13 Conducted Emission Requirements for Class A Equipment at AC Power Port

Figure 14 Conducted Emission Requirements for Class B Devices at the AC Power Port

Fig. 15 Asymmetric Mode Conducted Emission Requirements for Class A Equipment

Fig. 16 Asymmetric Mode Conducted Emission Requirements for Class A Equipment

Figure 17 Conductive Differential Mode Voltage Emission Requirements for Class B Devices

4 Provisions for EUT operation and test signals during measurement

For EUT with audio function, a sine wave signal of 1kHz is used unless otherwise specified.

An EUT capable of displaying video images, or with a video output signal port, operates as shown in Figure 18 and is set according to the parameters given in Figure 19.

Figure 18 How the display and video ports operate

Figure 19 Display and video parameters

5 Other methods of measurement of radiated emissions and related limits

Basic standards for 5.1 emission measurements and restrictions on the use of GTEM and RVC methods

For RVC measurements, the total radiated power should be converted to an equivalent free-space electric field value. The method specified in Appendix E of IEC61000-4-21: 2011[I6.7] should be adopted.

The limits applicable to GTEM are given based on the limits of 10m measurement distance in OATS and 3m measurement distance in FSOATS.

Figure 20. Basic standards used for radiative emission measurements and constraints using GTEM and RVC methods

5.2 Limits for Radiated Emission Measurements Using GTEM or RVC

21-25 show the limits of radiation emission measurements using GTEM or RVC.

Figure 21 Recommended limits for radiated emission below 1GHz for GTEM Class A equipment

Figure 22 Recommended limits for radiated emissions above 1GHz for GTEM Class A equipment

Figure 23 Recommended limits for radiated emission below 1GHz for GTEM Class B equipment

Figure 24 Recommended limits for radiated emission above 1GHz for GTEM Class B equipment

Figure 25 Recommended limits for radiated emissions above 1GHz for RVC Class B equipment

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