CISPR 32 Summary: Multimedia Equipment Emissions

At a glance

• Scope: emissions from multimedia equipment (MME), covering information technology equipment as well as broadcast receivers and audio/video equipment.
• It merged the former CISPR 22 (ITE) and CISPR 13 (broadcast receivers). Europe adopts it as EN 55032 and Korea as KN 32.
• Immunity requirements are covered separately by CISPR 35 (EN 55035, Korean KN 35).
• Besides emission limits it defines test setups, measurement methods and equipment classes (A/B).

Class A and Class B

Class B equipment also meets Class A limits, so many teams design to Class B when the final use is unclear.

Radiated emission limits (30 MHz – 1 GHz, quasi-peak)

Apply either the 3 m or the 10 m limits across the whole frequency range, not a mix. The 3 m limit is the 10 m limit plus 10 dB, the tabulated value rather than the computed +10.46 dB. Detector: quasi-peak, resolution bandwidth 120 kHz.

Radiated emission limits (above 1 GHz, 3 m)

Above 1 GHz the resolution bandwidth is 1 MHz and measurements are made at 3 m in a fully anechoic room (or a semi-anechoic room with absorbers on the floor). The upper frequency depends on the highest internal frequency of the EUT, up to 6 GHz.

AC mains port conducted emission limits (0.15–30 MHz)

Unit is dBµV, resolution bandwidth 9 kHz, measured with an artificial mains network (LISN/AMN). Both QP and average limits must be met. The public sources we checked disagree on the Class A figures, so they are intentionally not listed here; check the standard text.

Which items apply to which port

• Enclosure port: radiated emissions (tables above).
• AC mains port: conducted emissions (table above).
• Wired network ports (Ethernet, telecom lines): asymmetric (common-mode) conducted emissions, measured with an impedance stabilisation network (ISN/AAN) against voltage and current limits.
• Additional ports by equipment type, such as broadcast tuner, antenna and optical ports.

Test setup essentials

• Below 1 GHz, tabletop EUTs sit on a non-conductive table 0.8 m above the floor and floor-standing EUTs on an insulating support above the ground plane. Above 1 GHz the standard prescribes a different height and setup, so check the text.
• Radiated emissions below 1 GHz: scan antenna height 1–4 m, rotate the turntable 360°, measure both vertical and horizontal polarisation and compare the maximum with the limit.
• Mains port: use a 50 Ω // (50 µH + 5 Ω) V-type LISN and measure both L and N.
• A typical flow is a fast peak pre-scan, followed by QP and average measurements only at frequencies close to the limit.

Practical checkpoints

• Design to at least 3–6 dB of margin to absorb lab-to-lab spread and measurement uncertainty. The "Limit margin" calculator helps with the decision.
• Frequent radiated-emission culprits: harmonics of fast clocks and switching supplies, common-mode current on cables, ground discontinuities, aperture (slot) leakage. If a ferrite on the cable helps, common-mode current is the cause.
• Test-distance conversion (3 m ↔ 10 m) is for estimates only; use the tabulated limit for the actual distance when judging compliance.
• The rule for comparing a reading with the limit follows the uncertainty criteria of CISPR 16-4-2 and your certification body’s policy.

Official sources

• The IEC webstore (https://webstore.iec.ch) lists the current CISPR 32 edition and its amendments.
• For Korean certification check the latest revision of the competent authority’s notice (including KN 32/KN 35).