CISPR 32

CISPR 32 applies to multimedia equipment with a rated AC or DC supply voltage not exceeding 600 V. It establishes electromagnetic emission requirements to protect radio services from interference and specifies repeatable measurement methods. Multimedia equipment may combine information technology, audio, video, broadcast-reception and other multimedia functions.

This guide is based on CISPR 32:2015+A1:2019, Edition 2.1, which incorporates Amendment 1:2019 and Corrigendum 1:2016. The numerical tables below summarise the applicable Class A and Class B emission limits, frequency ranges and measurement requirements. For compliance testing, the applicable edition and regional adoption, such as EN 55032, should be confirmed before establishing the test program.

CISPR 32 addresses electromagnetic emissions, while immunity requirements are covered separately by CISPR 35 / EN 55035. Both standards may be relevant to a multimedia product’s EMC compliance assessment. Our EMC testing service supports manufacturers with test planning, emissions measurements, troubleshooting and regulatory compliance.

Typical products to assess include computers, servers, displays, printers, scanners, network switches, routers, televisions, set-top boxes, audio systems and equipment combining several multimedia functions. Applicability depends on the standard’s definitions and the functions provided by the product.

CISPR 32 specifies emission requirements for different equipment ports, including the enclosure, AC and DC power ports, wired network ports, antenna ports, broadcast receiver tuner ports and RF modulator output ports, where applicable. The required measurements depend on the function of each port, its intended connections and the applicability conditions defined in the standard. Not all ports are subject to the same emission limits or measurement procedures.

For a product with a radio function, plan the separate transmitter, receiver and RF-exposure requirements alongside the multimedia emissions work. See our audiovisual and IT testing services and RF testing services.

CISPR 32 is an international emissions standard. EN 55032 is its European adoption. The applicable edition, amendments and regulatory citation must be established for the intended market; the numerical summaries on this page do not establish the current harmonised status of an EN publication.

For European market access, emissions results can contribute to the technical evidence for the applicable conformity assessment. They do not, by themselves, demonstrate every obligation for CE marking. Review our CE marking EMC and RED testing service when defining the wider program.

For the United States and Canada, review the relevant FCC requirements and ISED requirements separately. Similar measurement concepts do not make the limits, procedures or approval routes interchangeable.

CISPR 32 selects measurements by equipment class and port. The following overview identifies the principal assessments; a product-specific plan determines which apply.

Class A and Class B

The class is established from the intended use. It is not selected after testing simply to accommodate a failing result.

How far above 1 GHz must the radiated scan extend?

CISPR 32 Table 1 determines the upper radiated emission measurement frequency based on F_x, the highest internal frequency of the equipment as defined by the standard. This frequency should be identified from the equipment design, including relevant internal clock and operating frequencies, rather than relying only on the processor’s advertised clock speed.

Special conditions: If the highest internal frequency is unknown, measurements extend up to 6 GHz. Outdoor units of home satellite receiving systems are subject to special requirements extending the measurement frequency up to 18 GHz. For FM and TV broadcast receivers, certain local oscillator and tuned frequencies are excluded when determining F_x, as specified in the standard.

Engineering consideration: Not every multimedia product requires radiated emission measurements up to 6 GHz. The applicable upper measurement frequency depends on the equipment’s internal frequencies and the requirements of CISPR 32.

Edition reference: The table summarises CISPR 32:2015, Table 1. The applicability of Amendment 1:2019 should be verified when using CISPR 32:2015+A1:2019 for compliance assessment.

Edition and scope: the following numerical summaries are derived from CISPR 32:2015. They distinguish the measurement facility, detector, bandwidth, class and units. They are selected limit summaries, not a replacement for the complete standard or its later amendments.

Radiated emissions: OATS/SAC, 30 MHz to 1 GHz

For an open-area test site (OATS) or semi-anechoic chamber (SAC), the 2015 requirements provide the following 10 m and 3 m alternatives. Use one applicable arrangement across the full range.

These are OATS/SAC limits. Fully anechoic room (FAR) limits are different and are shown separately below. For FM receiver local-oscillator emissions and harmonics, consult Table A.6 rather than assuming that the general Class B limits apply.

Radiated emissions: fully anechoic room, 30 MHz to 1 GHz

The FAR alternatives use a quasi-peak detector with 120 kHz bandwidth. The relevant facility-validation and equipment-size conditions in Table A.1 also apply.

Radiated emissions above 1 GHz

The following limits apply at 3 m in the free-space measurement arrangement (FSOATS), using 1 MHz bandwidth. Assess both average and peak requirements, subject to the source-specific exception described below. Stop at the upper frequency established from Table 1.

Annex A excludes emissions caused by qualifying high-voltage arc/spark breakdown events from the peak limits in Tables A.3 and A.5; their average limits still apply. Other emissions remain subject to both detector requirements. Tables A.6 and A.7 address additional receiver-specific cases.

AC mains conducted emissions

Measure the AC mains port using an AMN and 9 kHz bandwidth. QP means quasi-peak; AV means average. Both detector requirements apply across the band.

Asymmetric-mode conducted emissions: AAN voltage method

This table summarises only the asymmetric artificial network (AAN) voltage method, using 9 kHz bandwidth. It applies to the relevant listed ports when intended for cables longer than 3 m. Tables A.11 and A.12 and Annex C determine the full applicability and measurement procedure.

Covered port categories include wired network ports, optical-fibre ports with metallic shields or tension members, and the antenna-related ports listed for the relevant equipment class. The Class B table also lists broadcast-receiver tuner ports. A mains port that also functions as a wired network port is assessed against the corresponding AC mains limits. Screened ports are measured with the specified 150 Ω common-mode termination.

The capacitive voltage probe/current-probe methods have additional voltage and/or current limits and procedure-specific conditions. Those alternative methods are not represented by the AAN-only table above. Differential-voltage requirements for certain receiver and modulator ports are addressed separately in Table A.13.

Reading the limit lines correctly

• An arrow indicates a limit that changes linearly with the logarithm of frequency, not a free choice between two levels.
• At a step between two limits, the lower limit applies at the transition frequency.
• dB(uV/m) is field strength; dB(uV) is voltage. These quantities are not interchangeable.
• OATS/SAC and FAR limit sets are distinct. Select the applicable facility method rather than applying a distance correction to an unrelated table.
• Use the complete applicable table, notes and measurement procedure for a compliance decision.

Configure the equipment with representative peripherals, modules, cables and loads. Exercise its primary functions during the measurement. Where a port is specified for both screened and unscreened cables, the 2015 requirements call for assessment with both cable types. Annex A calls for Ethernet measurements at the highest supported data rate.

Modules marketed separately are assessed with a representative host under Clause 6.2. Document the host and modules used. For a host product, select modules that make the system representative of typical use.

Display and video patterns: 2016 corrigendum

Corrigendum 1:2016 replaces the display/video exercise table. The following is an original-language summary of the corrected pattern hierarchy.

The colour-bar patterns also apply to monochrome displays using greyscale. Exercise each display/video port as required by B.2.2. Where a pattern must be modified to exercise a primary function, retain the prescribed image over most of the display; the corrigendum recommends confining modifications to the upper or lower half where possible. Refer to ITU-R BT.471-1 for the specified colour-bar examples.

Record the operating state

Provide software and firmware versions, mode-selection instructions, display settings, network traffic and accessory details. The report should identify the tested class and operating modes, describe how ports were exercised, and include enough setup information and photographs to support reproducibility.

Use EMC pre-compliance testing to investigate likely emissions problems while design changes remain practical. Start with representative power supplies and interfaces; a quiet prototype with inactive ports may not represent the finished product.

Separate the source from the coupling path

When investigating a peak, compare operating modes and repeat measurements after controlled changes. Check clocks, switching converters and interface activity, then investigate how noise reaches external cables or enclosure openings. Change one relevant variable at a time and keep a record of the result.

Prepare for a useful quotation

Send the product description, intended markets, proposed classification, supply ratings, port list, radio functions, model variants and available samples. Include previous results and the required delivery date. These details help define the test matrix and setup effort.

Plan the evidence, not just the test slot

Agree the report contents and how the tested model, accessories and configuration will be identified. If the design changes after testing, review the change before relying on the original results for the revised product.

Discuss your multimedia equipment emissions test program.

• Confusing Class A and Class B or selecting a class without establishing the intended environment.
• Applying SAC/OATS limits to a FAR setup or comparing results measured at different distances without the correct procedure.
• Stopping the radiated assessment before the upper frequency required by Table 1.
• Using a development workload that leaves a primary display, network interface or other function inactive.
• Changing the supplied adapter, cables, accessories or enclosure after testing without reviewing their effect.
• Using the wrong detector, bandwidth, coupling method or port classification when comparing a measured peak with a limit.