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Chap 5: EMC Chap 5: EMC

Regulations and Regulations and Measurements Measurements

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Agenda Civilian Regulations. Measurement of Radiated Emissions. Test-site Calibration.

Measurement of Conducted Emissions. Measurement of Radiated EMI Susceptibility. Measurement of Conducted EMI Susceptibility. Electrostatic Discharge Test.

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Civilian Regulations EMC: ability of two or more electrical devices to operate

simultaneously without mutual interference. EMC Regulations: established absolute limits for radiated

and conducted emission. Requirements on susceptibility

to EMI emissions are specified in E-Norms. Civilian equipment to be marketed within EEA must

satisfy EEC Directive on EMC. Enforcement and penalties are matters for national government.

Civilian equipment to be marketed in US must conform to

FCC Regulations on EMC before it can be advertised or sold commercially.

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International International

IEC

TC77 CISPR

European European

ETSI CENELEC

United States United States

DOD FCC

ACEC

ETS 300XXX TC110

EN50XXX EN55XXX EN60XXX

CFR 47 Part 15

MIL-STD-461B MIL-STD-462

IEC1000 IEC801

IEC555

CISPR-16 CISPR-23

IEC - International Electrotechnical Commission, operates closely with ISO.CISPR - International Special Committee on Radio Interference (titl e in French), founded 1934.CENELEC - European Committee for Electrotechnical Standardization.ETSI - European Telecommunication Standards Institute.ACEC - Advisory Committee on EMC

Standards and Standard Making Bodies

FCC - Federal Communication Commission Dod - Department of Defense.

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European EMC Directive

Introduced in 1989 (89/336/EEC), fully enforced Jan 1996. Requires each EEA member state to introduce legislation

(Competent Authority) by transposing the EMC Directive in

its own style. The technical requirements are contained in harmonised

standards, ie. The European Norms (EN) by CENELEC and European Telecommunications Standards (ETS) by ETSI.The IEC1000 documents and CISPR publications form a set

of Basic Standards which are reference by documents from CENELEC.

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European EMC Directive European Economic Area (EEA)

European Union (EU)

Austria Ireland

Belgium Italy Denmark Luxembourg Finland Netherlands France Portugal Germany Spain Greece Sweden

United Kingdom

Iceland Liechtenstein

Norway

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European EMC Directive Products complying with all relevant directives carry a CE

mark. All products to be marketed in EEA must bear the CEmark.

Products with CE mark cannot be stopped at the borders of member states without positive evidence of a problem.

EMC requirements include both emission and susceptibility,from 150kHz to 30MHz for conducted interference and 30MHz to 1GHz for radiated interference.

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European EMC Directive Exclusions: Exclusions: Second-hand apparatus, electromagnetically benign apparatus, apparatus

for export to 3rd country outside EEA. Apparatus covered by other directives, eg. Medical devices, motor

vehicles, equipment in aircraft, marine equipment. Apparatus partially covered - Telecommunication Terminal Equipment

(TTE Directive) and others. Spare parts/components performing no direct function (Resistors,

capacitors, transistors, integrated circuits, cables, connectors, batteries,CRT, LCD, LED display screen.

Included: PC cards, modem cards, controller modules, disc drive, battery chargers,

DIY kits

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EMC Certification Self certification - manufacturer/authorised representative issues a

Declaration of Conformity to declare that the apparatus conforms to relevant harmonized standards, no specific requirement to perform test. However relevant authorities in member countries may conduct random sampling checks.

Technical construction file - for cases where no harmonised standards or incomplete standards. Manufacturer creates a file,describes how compliance with protection objectives was achieved.ACompetent Body will review results and issues certificate.

EC Type Examination - applies only to radio transmitters or combined transmitters and receivers. Testing must be performed,and a Type Examination Certificate from a Notified Body is required.

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ENFORCEMENT & PENALTIES The Responsible Person (manufacturer / authorised

representative / importer) must be established within the EEA.The obligation is to retain the necessary documentation at the disposal of the Competent Authorities for 10 years after the last apparatus has been placed on the market.

Enforcement and penalties are matters of national governments and varies for one country to another.

Withdrawal of product from the market will be ordered. Fines in most EEA countries. Fines/Imprisonment: Belgium, Finland, UK.

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Federal Communications Commission

Technical requirements are detailed in Code of Federal Regulation (CFR) 47, part 15.

Only covers emission. Susceptibility is self-regulated by

manufacturers. Distinguishes between intentional (subpart C) and

unintentional radiation (subpart B) - 23 June 1992. Limits apply to conducted interference on mains lead for

frequencies from 450kHz to 30MHz. Radiated interference covers from 30MHz to 40GHz.

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Federal Communications Commission

Devices exempted from specific technical Devices exempted from specific technical standards of Part 15...standards of Part 15...

Apparatus used exclusively in motor vehicles, aircraft. Apparatus used exclusively in electronic control or power

system utilized by public utility or in an industrial plant. Apparatus used exclusively in industrial, commercial or

medical test equipment.

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FCC Certifications Self certification - through Declaration of Conformity (DoC) for

digital devices (using clock signal exceeding 9 kHz). For all other types of equipment, manufacturer must obtain FCC

certification. Otherwise, he must verify the compliance and keep the test results on file, subject to inspection by FCC.

FCC regulations also require unintentional radiating devices to provide user instructions which contain suggested remedies in the case of interference to sensitive devices such as radio receivers.

Upper frequency of measurement : 1000 MHz for devices operated below 108 MHz 5th harmonic of highest frequency if operated above 1000 MHz

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Type of Devices Class-A devices are those intended for commercial/industrial use. Class-B devices are those intended for residential use. Since Class-B devices are more likely to be places near television

receiving antenna (and other household appliances), the rules governing Class-B devices are more stringent.

frequencyClass-A limits

at 10 mClass-B limits

at 3 mClass-B limits

at 10 m30 - 88 MHz88 - 216 MHz

216-960 MHzAbove 960 MHz

90 V/m150 V/m

210 V/m300 V/m

100 V/m150 V/m

200 V/m500 V/m

30 V/m45 V/m

60 V/m150 V/m

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Measurement of Radiated Emissions Open Area Test Site (OATS)...Open Area Test Site (OATS)...

EUT

Turntable Ground Plane

To Test Receiver

Height varied over 1m to 4m at each

test frequency

0.8m

Measurement distance L = 3m or 10m

Antennas...Antennas...Typically broadband Biconical - 30-300MHz Log Periodic - 0.2-2 GHz Bilog - 30-2000 MHz

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Open Area Test Site Large outdoor area with a ground screen (steel mesh wire) and

free of obstacles and interfering ambient fields. Repeatability depends on ground (soil) conductivity and

ambient conditions (noise, temperature, humidity).

EUT must be away from conductive, dielectric, or magnetic materials. Site may be enclosed with non-conductive materials such as canvas or air-supported plastic for protection against weather.

Half-wave dipole is specified. Impedance mismatch between

antenna and receiver will affect accuracy of measurements.Antenna length must be adjusted for each frequency.

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Semi-Anechoic Chamber Shielded room covered with EM wave absorbers over the entire

inner surfaces except the floor. Controlled environment, with all-weather capability and minimum

ambient electromagnetic interference, offers a much more flexible and repeatable facility than OATS.

For high-speed scanning over a band of frequencies, use wideband antennas - Biconical (30 - 300 MHz), Log-periodic (200 to 2000 MHz), Bilog (30 - 2000 MHz).

Both vertical polarisation and horizontal polarisation

components of radiated fields must be measured. In case of dispute, measurement using OATS and half-wave dipole shall take precedence.

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Measurement Procedure

Conductive floor causes emission to double at certain angles.Radiated emissions must be measured in all directions from the radiating device - Accomplished by slowly rotating the EUT and,at the same time move the receiving antenna upward (or downward) to record the worst-case radiation.

The EUT shall be in its typical complete configuration and operated in its normal manner, with all interconnect peripheral equipment connected such that the emissions are maximised.

Source Receiver

Image

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Detection Techniques

Peak detection: received voltage at each frequency is measured over a period to find the peak value (CR d = ).

Quasi-peak detection (QP): the detector has a certain discharging time-constant (CR d ) such that any voltage spike will be suppressed. Voltage reading always less than or equal to peak

detection. Measurement time 2 to 3 times longer than peak detection. Regulatory limits are based on QP values.

IFFilter

R c

C R dAntenna Factor(dB)=Electric Field (dB V/m) - Received Voltage(dB V)

Electric Field ( V/m) = Received Voltage ( V) Antenna Factor (m -1 )

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Test-site Calibration Before any test-site can be used, it must be checked with a

known source. Use half-wave dipole as transmitter, placed 2 m above the

conductive floor (in place of EUT).

Measure received voltage using another half-wave dipole. Vary its height (1 m - 4 m) and record the highest field intensity. Site Attenuation: ratio of the transmitted voltage to the received

voltage. Test-site is acceptable if the measured site attenuation is within

4 dB compared to theoretical value at each frequency.

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Conducted Emissions Electronic device can emit high-frequency noise through its AC

power cord and affect other appliances that share the same power source.

Impedance looking into the wall outlets affects the amount of

noise that is conducted. The impedance varies over the measurement frequency range, and from outlet to outlet. Line Impedance Stabilisation Network (LISN) present a constant

impedance (50 ohms) between the Phase wire and Earth wire,and between the Neutral wire and Earth wire.

LISN also acts as filter to prevent external conducted noise on the power line from contaminating the measurement.

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Line-Impedance Stabilization Network Phase

Neutral

Earth

EUT

1 F1 F

0.1 F 0.1 F

1 k 1 k 50

Transient Suppressor

Spectrum Analyzer

VN

VP

50

50

Power outlet

Frequency Class-A limits Class-B limits0.45 - 1.705 MHz1.705 - 30 MHz

60 dB V69.5 dB V

48 dB V48 dB V

The frequency range for EN conducted emission is 150 kHz to 30 MHz - different LISN should be used.

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Measurement of Conducted Emissions

EUT

Ground Plane 2mX2m (min)

To Receiver

0.8m

Vertical Ground Plane (wall of screened enclosure)

0.4m 0.8m Line Impedance

Stabilization Network (LISN)

Non-conducting table

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Measurement of Radiated EMI Susceptibility

Signal Source

AGC &Modulation Power Amp.

M u l t i p l e x e r

EUT

Anechoic Chamber

Power supply & ancillary equipment

IEEE-488 Control Bus

Screen Room

Biconical

Log periodic

Field Strength Monitor

Absorber

Control & Data Capture

Severity level V/m1 12 33 10

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Test Procedure (EN 61000-4-3)

80 - 1000 MHz sweep, 80% modulation depth with 1 kHz sinewave, 4 faces 2 polarisation.

Additional test at 900 MHz with 200-Hz pulse modulation.

Field Uniformity of Anechoic Chamber -0/+6 dB over 12 out of 16 points within 1.5m 1.5m square, 0.8m above the floor.

TEM Cell can be used. Applicable severity level depends on the expected

operating EMR environment.

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Performance Criteria Only the EMI effects should be recorded, no specific

definition for performance degradation. Grade A: Normal performance within specification limits.

Grade B : Temporary degradation or loss of function which is self recoverable.

Grade C : Temporary degradation or loss of function which requires operator intervention or system reset.

Grade D : Degradation or loss of function which is not recoverable.

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Conducted EMI Susceptibility (EN 6100-4-4)

EUT 150 Ohm

50 Ohm HV source

Ground reference

Coupling/Decoupling Network (CDN)

Current source Level

Monitor

150 Ohm

150 Ohm

Decoupling/Impedance Stabilizer Network on

all untested cables

Ancillary Units

Voltage Injection

Current Injection

Insulation

Electrical Fast Transient/Burst (EFT/B)

Signal, data & control line: 0.25, 0.5,1,2 kV,5/50ns pulses, repetition rate 5 kHz.

Both polarities (btw. terminal and ground) Power supply lines: 0.5,1,2 or 4 kV

Surge 0.5,1,2, or 4 kV line-to-line, and line-to-earth,

different source impedance

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Voltage Dips/Interruptions/Variations Dips and Short Interruptions: 0%, 40%, and 70% of nominal

50/60-Hz voltage for a duration of 0.5 to 50 periods. Short term variation taking 2 seconds to reach 40% and 0%

of nominal voltage, 1 second in the test level, and then 2

seconds to recover to nominal voltage.2 s 2 s

1 s

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Electrostatic Discharge Test (EN 61000-4-2)

EUT

Conducting plane

Insulation

Ground Reference plane

EUT Supply

Ground connection

Direct application

Indirect application

High Voltage Supply

10 positive / negative zaps to each accessible point,

2 - 15 kV (8 kV contact discharge)

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Good Luck !!