CISPR 22

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CISPR 22: 1997 Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement

Definitions

Information technology equipment (ITE)

Any equipment:

1. which has a primary function of either (or a combination of) entry, storage, display, retrieval, transmission, processing, switching, or control, of data and of telecommunication messages and which may be equipped with one or more terminal ports typically operated for information transfer;
2. with a rated supply voltage not exceeding 600V.

It includes, for example, data processing equipment, office machines, electronic business equipment and telecommunication equipment.

Any equipment (or part of the ITE equipment) which has a primary function of radio transmission and/or reception according to the ITU Radio Regulations are excluded from the scope of CISPR 22.

Note – Any equipment which has a function of radio transmission and/or reception according to the definitions of the ITU Radio Regulations should fulfil the national radio regulations, whether or not this publication is also valid.

Equipment, for which all disturbance requirements in the frequency range are explicitly formulated in other IEC or CISPR publications, are excluded from the scope of this publication.

Telecommunication ports

Ports which are intended to be connected to telecommunication networks (e.g. public switched telecommunication networks, integrated services digital networks), local area networks (e.g. Ethernet, Token Ring) and similar networks.

Classification of ITE

ITE is subdivided into two categories denoted class A ITE and class B ITE.

Class B ITE

Class B ITE is a category of apparatus which satisfies the class B ITE disturbance limits.

Class B ITE is intended primarily for use in the domestic environment and may include:

	Equipment with no fixed place of use; for example, portable equipment powered by built-in batteries;
	Telecommunication terminal equipment powered by a telecommunication network;
	Personal computers and auxiliary connected equipment.

Note – The domestic environment is an environment where the use of broadcast radio and television receivers may be expected within a distance of 10 m of the apparatus concerned.

Class A ITE

Class A ITE is a category of all other ITE which satisfies the class A ITE limits but not the class B ITE limits. Such equipment should not be restricted in its sale but the following warning shall be included in the instructions for use:

Warning

This is a class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.

Limits for conducted disturbance at mains terminals and telecommunication ports.

The equipment under test (EUT) shall meet the limits in tables 1 and 3 or 2 and 4, as applicable, including the average limit and the quasi-peak limit when using, respectively, an average detector receiver and quasi-peak detector receiver and measured in accordance with the methods described in clause 9 of CISPR 22. Either the voltage limits or the current limits in table 3 or 4, as applicable, shall be met except for the measurement method of C.1.3 of CISPR 22 where both limits shall be met. If the average limit is met when using a quasi-peak detector receiver, the EUT shall be deemed to meet both limits and measurement with the average detector receiver is unnecessary.

If the reading of the measuring receiver shows fluctuations close to the limit, the reading shall be observed for at least 15 s at each measurement frequency; the higher reading shall be recorded with the exception of any brief isolated high reading which shall be ignored.

Table 1 – Limits for conducted disturbance at the mains ports of class A ITE

Frequency range MHz	Limits dB(m V)
	Quasi-peak	Average
0.15 to 0.50	79	66
0.50 to 30	73	60
Note – The lower limit shall apply at the transition frequency.

Table 2 – Limits for conducted disturbance at the mains ports of class B ITE

Frequency range MHz	Limits dB(m V)
	Quasi-peak	Average
0.15 to 0.50	66 to56	56 to 46
0.50 to 5	56	46
5 to 30	60	50
Note 1 – The lower limit shall apply at the transition frequency. Note 2 – The limit decreases linearly with the logarithm of the frequency in the range 0.15 MHz to 0.50 MHz

Table 3 – Limits of conducted common mode (asymmetric mode) disturbance at telecommunication ports in the frequency range 0.15 MHz to 30 MHz for class A equipment

Frequency range MHz	Voltage limits dB(m V)		Current limits dB(m A)
	Quasi-peak	Average	Quasi-peak	Average
0.15 to 0.50	97 to 87	84 to 74	53 to 43	40 to 30
0.50 to 30	87	74	43	30
Note 1 – The limit decreases linearly with the logarithm of the frequency in the range 0.15 MHz to 0.50 MHz Note 2 – The current and voltage disturbance limits are derived for use with an impedance stabilization network (ISN) which presents a common mode (asymmetric mode) impedance of 150 W to the telecommunication port under test (conversion factor is 20 log 10 150 / I = 44 dB).

Table 4 – Limits of conducted common mode (asymmetric mode) disturbance at telecommunication ports in the frequency range 0.15 MHz to 30 MHz for class B equipment

Frequency range MHz	Voltage limits dB(m V)		Current limits dB(m A)
	Quasi-peak	Average	Quasi-peak	Average
0.15 to 0.50	84 to 74	74 to 64	40 to 30	30 to 20
0.50 to 30	74	64	30	20
Note 1 – The limit decreases linearly with the logarithm of the frequency in the range 0.15 MHz to 0.50 MHz Note 2 – The current and voltage disturbance limits are derived for use with an impedance stabilization network (ISN) which presents a common mode (asymmetric mode) impedance of 150 W to the telecommunication port under test (conversion factor is 20 log 10 150 / I = 44 dB). Note 3 – Provisionally, a relaxation of 10 dB over the frequency range of 6 MHz to 30 MHz is allowed for high-speed services having significant spectral density in this band. However, this relaxation is restricted to the common mode disturbance converted by the cable from the wanted signal.

Limits for radiated disturbance

The EUT shall meet the limits of tables 5 or 6 when measured at the measuring distance R in accordance with the methods described in clause 10 of CISPR 22. If the reading on the measuring receiver shows fluctuations close to the limit, the reading shall be recorded, with the exception of any brief isolated high reading, which shall be ignored.

Table 5 – Limits for radiated disturbance of class A ITE at a measuring distance of 10 m

Frequency range MHz	Quasi-peak limits dB(m V)
30 to 230	40
230 to 1000	47
Note 1 – The lower limit shall apply at the transition frequency. Note 2 – Additional provisions may be required for cases where interference occurs.

Table 6 – Limits for radiated disturbance of class B ITE at a measuring distance of 10 m

Frequency range MHz	Quasi-peak limits dB(m V)
30 to 230	30
230 to 1000	37
Note 1 – The lower limit shall apply at the transition frequency. Note 2 – Additional provisions may be required for cases where interference occurs.