Keysight Technologies Making EMI Compliance Measurements Application Note 02 | Keysight | Making EMI Compliance Measurements - Application Note Table of Contents Introduction to compliance measurements ........................................3 The compliance measurements process ............................................4 Compliance EMI receiver requirements ..............................................7 Requirements above 1 GHz .......................................................7 Conducted emissions measurements .................................................8 Conducted test setup ................................................................8 Coniguringthereceiver.............................................................8 Performing conducted emissions measurements ................... 10 Radiated emissions measurements ................................................... 12 Open site requirements ............................................................ 12 Radiated emissions test setup ................................................. 13 Measuring radiated emissions ................................................. 14 Placement of EUT for maximum signals ........................................... 15 Ambient plus EUT measurements ........................................... 15 Appendix A - Line impedance stabilization networks ...................... 16 Appendix B - Antenna factors ........................................................... 18 Appendix C - Basic electrical relationships ......................................20 Appendix D - Detectors used in EMI measurements .......................21 Appendix E - EMC regulatory agencies ............................................ 24 Glossaryofacronymsanddeinitions ...............................................26 03 | Keysight | Making EMI Compliance Measurements - Application Note Introduction to compliance measurements Electrical or electronic equipment that uses the public power grid or has potential for electromagnetic emissions must pass EMC (electromagnetic compatibility) requirements. These requirements fall into four broad types of testing: radiated and conducted emissions testing, and radiated and conducted immunity testing. Conducted emissions testing focuses on signals present on the AC mains that are generated by the equipment under test (EUT). The frequency range of these measurements is typically 9 kHz to 30 MHz. However, MIL-STD measurement may have a wider frequency range. Radiated emissions testing searches for signals being emitted from the EUT through space. The typical frequency range for these measurements is 30 MHz to 1 GHz or 6 GHz, although FCC regulations require testing up to 40 GHz. Figure 1 illustrates the difference between radiated emissions, radiated immunity, conducted emissions, and conducted immunity. Radiated immunity is the ability of a deviceorproducttowithstandradiatedelectromagneticields.Conductedimmunityis the ability of a device or product to withstand electrical disturbances on power or data lines. Immunity testing will not be covered in this document. For an electromagnetic compatibility problem to occur (such as when an electric drill interferes with TV reception), there must be a generator or source, a coupling path, and a receptor. Until recently, most efforts to remove EMC problems have focused on reducing the emissions of the source to an acceptable level—now both emissions and immunity tests are performed. Emission Figure 1. Four types of EMC measurements Immunity = Susceptibility 04 | Keysight | Making EMI Compliance Measurements - Application Note The compliance measurements process Before compliance measurements can be performed on a product, some preliminary questions must be answered: 1. Where will the product be sold (for example, the United States,Europe, or Japan)? 2. Whatistheclassiicationoftheproduct(forexample,informationtechnologyequipment(ITE);industrial,scientiic,ormedical(ISM);automotiveandcommunications)? 3. Where will the product be used (for example, home, commercial, light industry, or heavy industry)? With the answers to the above questions, you can determine which testing requirements apply to your product by referring to Tables 1a and 1b below. For example, if you have determined that your product is an ITE device that will be sold in the U.S., then you need to test the product to FCC Part 15 regulations. International regulations summary (emissions) CISPR FCC EN Description 11 Part 18 EN 55011 Industrial, scientiic, and medical 13 Part 15 EN 55013 Broadcast receivers 14 EN 55014 Household appliances/tools 15 EN 55015 Fluorescent lights/luminaries Measurement apparatus/methods 16-1-1 22 Part 15 25 EN 55022 Information technology equipment EN 55025 Automotive EN 50081-1,2 Generic emissions standards Table 1a. Comparison of regulatory agency requirements European Norms (EN) Equipment type Emissions Generic equipment EN 50081-1 Residential Light industrial Industrial EN 50081-2 Industrial, scientiic, medical products (ISM) EN 55011 Sound and broadcast receivers EN 55013 Household appliances EN 55014 Information technology equipment (ITE) EN 55022 Automotive EN55025 Table 1b. Major European requirements 05 | Keysight | Making EMI Compliance Measurements - Application Note European Norms EN55011(CISPR11)Industrial,scientiic,andmedicalproducts Class A: Used in establishments other than domestic areas. Class B: Suitable for use in domestic establishments. Group1:Laboratory,medical,andscientiicequipment.(Forexample,signalgenerators, measuring receivers, frequency counters, spectrum analyzers, switching mode power supplies, weighing machines, and electronic microscopes.) Group 2: Industrial induction heating equipment, dielectric heating equipment, industrial microwave heating equipment, domestic microwave ovens, medical apparatus, spark erosion equipment, and spot welders. (For example, metal melting, billet heating, component heating, soldering and brazing, wood gluing, plastic welding, food processing, food thawing, paper drying, and microwave therapy equipment.) EN55014 (CISPR 14) Electric motor-operated and thermal appliances for household and similar purposes, electric tools, and electric apparatus. Depending on the power rating of the item being tested, use one of the limits shown in Table 1c. EN55014 Conducted household appliances QP EN55014 Conducted household appliances AVE EN55014 Conducted < 700 W motors QP EN55014 Conducted < 700 W motors AVE EN55014 Conducted > 700 W < 1000 W motors QP EN55014 Conducted > 700 W < 1000 W motors AVE EN55014 Conducted > 1000 W motors QP EN55014 Conducted > 1000 W motors AVE EN55014 Radiated household appliances QP EN55014 Radiated household appliances AVE EN55014 Radiated < 700 W motors QP EN55014 Radiated < 700 W motors AVE EN55014 Radiated > 700 W < 1000 W motors QP EN55014 Radiated > 700 W < 1000 W motors AVE EN55014 Radiated > 1000 W motors QP EN55014 Radiated > 1000 W motors AVE Note: The conducted range is 150 kHz to 30 MHz and the radiated range is 30 MHz to 300 MHz. Table 1c. Tests based on power rating EN55022 (CISPR 22) Information technology equipment Equipment with the primary function of data entry, storage, displaying, retrieval, transmission, processing, switching, or controlling. (For example, data processing equipment, oficemachines,electronicbusinessequipment,andtelecommunicationsequipment.) Class A ITE: Not intended for domestic use. Class B ITE: Intended for domestic use. 06 | Keysight | Making EMI Compliance Measurements - Application Note Federal Communications Commission Equipment FCC Broadcast receivers Household appliances/tools Part 15 Fluorescent lights/luminaries Information technology equipment (ITE) Industrial, scientiic, medical products (ISM) Conducted measurements: 450 kHz - 30 MHz Part 18 Radiated measurements: 30 MHz - 1000 MHz, 40 GHz Table 1d. FCC regulations Federal Communications Commission (FCC) FCC Part 15 Radio frequency devices—unintentional radiators Equipment that unintentionally produces emissions that could interfere with other devices. (For example, TV broadcast receivers, FM broadcast receivers, CB receivers, scanning receivers, TV interface devices, cable system terminal devices, Class B personal computers and peripherals, Class B digital devices, Class A digital devices and peripherals, and external switching power supplies). Class A digital devices are marketed for use in a commercial, industrial, or business environment. Class B digital devices are marketed for use in a residential environment. For assistance, contact the agency for conformation of the applicable requirement— see Appendix E for contact information. 07 | Keysight | Making EMI Compliance Measurements - Application Note Compliance EMI receiver requirements ThereareseveralrequirementsformakingcomplianceEMImeasurements.Theirstisan EMI receiver that meets CISPR 16-1-11, such as the N9038A MXE EMI receiver. A CISPR 16-1-1 receiver must have the following functionality in the range 9 kHz - 18 GHz: – A normal ±2 dB absolute amplitude accuracy – CISPR-speciiedbandwidths(6dB)asindicatedinthechartbelow Bandwidth Frequency range 200 Hz 9 kHz to 150 kHz 9 kHz 150 kHz to 30 MHz 120 kHz 150 kHz to 1000 MHz 1 MHz impulse 1 GHz to 18 GHz Note:Thefrequencyresponseoftheiltersmustalsofallwithina“mask”deinedbyCISPR16-1-1. – Peak,quasi-peak,EMIaverage,andRMSaveragedetectorswithspeciiedcharge, discharge time, and meter constants for the quasi-peak detector (see Appendix D for a description of these detectors) – Speciiedinputimpedancewithanominalvalueof50ohms;deviationsspeciiedasVSWR – Beabletopassproductimmunityina3V/mield – Be able to pass the CISPR pulse test – Otherspeciicharmonicandintermodulationrequirements TheCISPRpulsetestconsistsofbroadbandpulsesofadeinedspectralintensityof varying repetition frequency presented to the EMI receiver. The quasi-peak detector mustmeasurethesepulsesataspeciiedlevel,withinaspeciiedaccuracy.Inorderto meetthispulsetest,itisimplied,butnotspeciied,thatthereceivermusthave: – Preselection—achievedbyinputiltersthattrackthereceivertuningtoreduce broadband noise overload at the front end mixer – Sensitivityanddynamicrange—theEMIreceivermusthaveanoiseloorlowenough to measure signals at low PRFs A recommended feature for ensuring accurate measurements is overload detection. To make an accurate measurement, the receiver must be in linear operating mode and not be in saturation at the front-end mixer because of large narrowband signals or broadband emissions. A useful overload detection scheme will alert the user to overload conditions in all frequency ranges and in all modes of operation. An advanced overload detectionandmeasurementschemewill“autorange,”orautomaticallyputinenough attenuationpriortotheirstmixertomeasurethesignalinnon-overloadconditions. Requirements above 1 GHz Regulations require a 1 MHz bandwidth for measurements above 1 GHz. In addition, no quasi-peak detector is required for measurements above 1 GHz. The CISPR pulse test is not required above 1 GHz, but excellent sensitivity in the measuring system is important toachievesuficientdynamicrangeinordertoperformthemeasurements. AccordingtocurrentFCCregulations,themaximumtestfrequencyistheifthharmonic ofthehighestclockfrequencyforan“unintentionalradiator”(forexample,computers without wireless connectivity) and the tenth harmonic for an intentional radiator (such as a cellular phone or wireless LAN). 1. Comite International Special des Perturbations Radioelectriques 08 | Keysight | Making EMI Compliance Measurements - Application Note Conducted emissions measurements Emissions testing is divided into conducted emissions and radiated emissions testing. Follow the steps outlined below to set up the test equipment, accessories, and EUT. Conducted test setup ANSIC63.4describesaspeciictestsetupforconductedemissions.FCCPart15details the limits for these tests. Refer to ANSI C63.4 for the latest conducted emissions setup— CISPR 22 shows a similar conducted test setup for ENs. Coniguringthereceiver Interconnect the EMI receiver, such as the Keysight Technologies, Inc. N9038A MXE, LISN, and EUT. The function of a LISN is detailed in Appendix A. 1. 2. 3. Disconnect the input to the receiver. Set up the correct frequency range by selecting CISPR Band B, which also selects the correct bandwidth. Select the correct range in the scan table and switch on the RF preselector. Based on the type of equipment and the regulatory agency requirements, select the appropriate limit line from a wide range of limits in the EMI receiver. Note: This sequence of steps for making a compliant measurement with the EMI measurement receiver assumes that the measurement setup and measuring receiver are compliant with the applicable standard and a system alignment has been completed, if required. Figure 2a. FCC Part 15 limits 09 | Keysight | Making EMI Compliance Measurements - Application Note Coniguringthereceiver(continued) 4. Next, load correction factors for the LISN from the transducer list available in the EMI receiver. Figure 2b. Transducer correction factors with LISN After loading the LISN correction factors and limit lines, and starting a scan, your display should look similar to Figure 3. Figure 3. Display with limit line and correction factors for conducted emission testing 10 | Keysight | Making EMI Compliance Measurements - Application Note Performing conducted emissions measurements At this point, the EMI receiver is set up with all of the correct parameters, including bandwidth, frequency range, LISN compensation, and limit line. However, before starting conducted measurements, consider the effect of the ambient environment on the results. The power cable between the LISN and the EUT can act as an antenna, which can cause false EUT responses on the display. To test that this phenomenon is not occurring, switch offtheEUTandcheckthedisplaytoensurethatthenoiseloorisatleast6dBbelowthe limit line as shown in Figure 4. Figure 4. Test for ambient signals Switch on the power to the EUT and observe the display. If there are no signals above the limit line, then your product passes the conducted emissions limit. Data and signals close to the limit may need to be collected for your report. Remember that line and neutral must be tested. If there are signals above the limit, closer analysis is needed. Figure 5. Conducted emissions from DUT 11 | Keysight | Making EMI Compliance Measurements - Application Note Performing conducted emissions measurements (continued) The next step is to perform a quasi-peak measurement on signals above the limit line. This is accomplished by placing the signal in the EMI receiver list and performing a remeasure using the selected detector. At this point, all of the measured signal values have been recorded. The product passes this test if no measured quasi-peak values are above the quasi-peak limit, and no measured average values are above the average limit; or no measured quasi-peak values are above the average limit. Figure 6. Conducted emissions failure QP measurement Remember that all lines—such as line and neutral or all phases—must be tested. If some of the values are above the quasi-peak level using the quasi-peak detector, and are also above the average limit with the average detector, then some troubleshooting and redesign is required. 12 | Keysight | Making EMI Compliance Measurements - Application Note Radiated emissions measurements Performing radiated emissions measurements is not as straightforward as performing conducted EMI measurements. There is the added complexity of the open air ambient environment, which can interfere with the emissions from the EUT. Fortunately, there are methods to differentiate between signals in the ambient environment such as TV, FM, and cellular radio. Open site requirements EUTs are measured in an open area test site (OATS). ANSI C63.4 and CISPR 16-1-1 specify the requirements for an OATS, including: – Preferred measurement distances of 3, 10, and 30 meters – Antenna positioning at 1 to 4 meter heights – Anareacalledthe“CISPRellipse”ofmajordiameter2Xandminordiameter _ √ 3•X,whereXisthemeasurementdistance;theellipsemustbefreeofany relectingobjects – A metal ground plane for the measurement area Majordiameter=2X Minordiameter=3•X X Antenna EUT Figure 7. The CISPR ellipse For complete details on OATS requirements, see CISPR 16-1-1 and ANSI C63.4, as well as ANSI C63.7. In addition, ANSI C63.7 describes OATS construction. Note: 10 meter anechoic chambers and GTEM cells can also be used for radiated compliance measurements. 13 | Keysight | Making EMI Compliance Measurements - Application Note Radiated emissions test setup Note: The following sequence of steps for making a compliant measurement with the analyzer assumes that the measurement setup is compliant with the applicable standard. 1. Arrange the antenna, EUT, and EMI receiver as shown in Figure 8. Separate the antennaandtheEUTby3meters(10metersifspeciiedbytheregulation). CISPR and ANSI require the EUT to be in worst-case mode of operation (for example, with cables and monitor attached). CISPR radiated EMI test setup 1-4 meters above ground plane Antenna Equipment under test EMI receiver 360° Table is 80 cm high, non-conductive Ground plane Figure 8. Radiated test setup 2. 3. Use Table 1 to determine the regulation for which your product must be tested. Set up the EMI receiver for the correct span, antenna correction factors, and limit line with a margin. In this case, we are testing to the FCC Part 15, Class B, 3-meter limit. Load in the appropriate limit line from the available limits in the receiver. Figure 9. Loading FCC 3-meter Class B limit 14 | Keysight | Making EMI Compliance Measurements - Application Note Radiated emissions test setup (continued) Figure 10. Load correction factors for the antenna Load the appropriate antenna correction factors from the receiver. Since these are typical correction factors, you may need to edit them using the receiver's editing features. So far, you have arranged the equipment with the EUT 3 meters from the antenna, chosen the appropriate limit line, and corrected the display for antenna loss. Measuring radiated emissions The next step is to evaluate the radiated emissions from your product. With the EUT off, sweep the frequency range of interest. This gives you a good idea of the ambient signal levels. The ideal situation is to have all the ambient signals below the limit line. In many cases, they are not, so it’s a good idea to measure and record them. The amplitude and frequency of the ambient signals above the limit or margin can be stored in the receiver's signal list for future comparison and removal. Figure 11. Ambient signals placed in signal list 15 | Keysight | Making EMI Compliance Measurements - Application Note Placement of EUT for maximum signals (manual measurement process) Radiated emissions from electronic devices are not uniform. The strongest emissions may be from the rear panel, front panel, or slots in the shielding. To ensure that you are measuring the worst-case emissions from your device, follow the steps below: 1. 2. With the EMI receiver adjusted to view the span of interest, move the EUT through a 360° rotation in 45° increments At each 45° step, note the amplitude of the largest signal—save the screen to an internalileforlaterreference After all the screens have been captured, upload them into a graphics application so you cancomparethescreencapturesside-by-side.Insomecases,youmayindthatthere are worst-case emissions for different frequencies at different positions. For example, youmayindworst-casefor100MHzemissionsat90°,andat270°for200MHz.Inthis example, the emissions tests must be performed at both positions. If you are not sure whether the signal you are looking at is an ambient or EUT signal, switch off the EUT—an ambient signal will not change. Worst-case emissions must be found for both horizontal and vertical antenna polarizations. Ambient plus EUT measurements Orient the EUT to one of the worst-case positions. There may be more than one EUT position with emissions above the limit line. A quasi-peak measurement must be performed on each of these above-the-line emissions. If the quasi-peak measurement still indicates a failure, then some troubleshooting and repair is required. The solution could be as simple as poor cable grounding or unwanted slots in the shielding. Ifthereareseveralsignalsabovethelimitthatarenotidentiiedasambientsignals,you should zoom in on one or two at a time, measuring the quasi-peak value of each. Using software to perform the above processes allows for more repeatable measurements and documentation. Figure 12. Ambient environment plus DUT emissions 16 | Keysight | Making EMI Compliance Measurements - Application Note Appendix A Line impedance stabilization networks Purpose of a LISN A line impedance stabilization network serves three purposes: 1. 2. 3. The LISN isolates the power mains from the EUT. The power supplied to the EUT must be as clean as possible. Any noise on the line will be coupled to the EMI receiver and interpreted as noise generated by the EUT. The LISN isolates any noise generated by the EUT from being coupled to the power mains. Excess noise on the power mains can cause interference with the proper operation of other devices on the line. The signals generated by the EUT are coupled to the EMI receiver using a high-pass ilter,whichispartoftheLISN.Signalswhichareinthepassbandofthehigh-pass iltershowa50Ωload,whichistheinputtotheEMIreceiver. LISN operation The diagram in Figure A-1 below shows the circuit for one side of the line relative to earth ground. Line impedance stabilization network (LISN) 50 µH From power source 0.1 µF 1 µF 1000W To EUT To EMI receiver (50 W) Impedance (ohms) 60 50 40 30 20 10 .01 .1 1 10 100 Frequency (MHz) Figure A-1. Typical LISN circuit diagram The1µFcapacitor-incombinationwiththe50µHinductor,istheilterthatisolates the mains from the EUT. The 50 µH inductor isolates the noise generated by the EUT from the mains. The 0.1 µF capacitor couples the noise generated by the EUT to the EMIreceiver.Atfrequenciesabove150kHz,theEUTsignalsarepresentedwitha50Ω impedance. The chart in Figure A-1 represents the impedance of the EUT port versus frequency. 17 | Keysight | Making EMI Compliance Measurements - Application Note Appendix A (continued) Types of LISNs Types of LISNs H N V symmetric sy un V1 V c ri et m m 1 1/2 sy ric et m V Ground mm m m sy 2 V sy un m et un ric V asymmetric V-LISN etric 1/2 V sy mm etric V 2 unsymmetric Vector diagram V-LISN: Unsymmetric emissions (line-to-ground) -LISN: Symmetric emissions (line-to-line) T-LISN: Asymmetric emissions (mid point line-to-line) Figure A-2. Three different types of LISNs The most common type of LISN is the V-LISN. It measures the asymmetric voltage between line and ground. This is done for both the hot and the neutrallines,orforathree-phasecircuitina“Y”coniguration,between each line and ground. There are some other specialized types of LISNs. A delta LISN measures the line-to-line or symmetric-emissions voltage. The T-LISN, sometimes used for telecommunications equipment, measures the asymmetrical voltage, which is the potential difference between the midpoint potential between two lines and ground. 18 | Keysight | Making EMI Compliance Measurements - Application Note Appendix B Antenna factors Field strength units RadiatedEMIemissionsmeasurementsmeasuretheelectricield.Theieldstrengthis calibratedindBμV/m.FieldstrengthindBμV/misderivedfromthefollowing: P t = total power radiated from an isotropic radiator PD=thepowerdensityatadistancerfromtheisotropicradiator(farield) PD = P t/4πr 2 R=120πΩ PD = E2 /R E2 /R = P t/4πr 2 E = (P t x 30)1/2 /r (V/m) Farield*isconsideredtobe>λs/2π *Farieldistheminimumdistancefromaradiatorwheretheieldbecomesaplanarwave. Antenna factors Thedeinitionofantennafactorsistheratiooftheelectricieldinvoltspermeterpresent at the plane of the antenna, versus the voltage out of the antenna connector. Note: Antenna factors are not the same as antenna gain. Antenna factors Biconical @ 10m dB/m 30 Log periodic @ 1m 25 20 15 10 5 0 200 400 600 Frequency, MHz 800 1000 Ein Linear units: AF = Antenna factor (1/m) AF = E = Electric field strength (V/m) V out V = Voltage output from antenna (V) Log units: AF(dB/m) = E(dBµV/m) - V(dBµV) E(dBµV/m) = V(dBµV) + AF(dB/m) Figure B-1. Typical antenna factor shapes 19 | Keysight | Making EMI Compliance Measurements - Application Note Appendix B (continued) Types of antennas used for commercial radiated measurements Biconical antenna (30 - 300 MHz) Blah Broadband antenna (30 - 1000 MHz) Log periodic antenna (200 - 1000 MHz) Figure B-2. Antennas used in EMI emissions measurements There are three types of antennas used for commercial radiated emissions measurements. Biconical antenna: 30 MHz to 300 MHz Log periodic antenna: 200 MHz to 1 GHz (the biconical and log periodic overlap frequency) Broadband antenna: 30 MHz to 1 GHz (larger format than the biconical or log periodic antennas) 20 | Keysight | Making EMI Compliance Measurements - Application Note Appendix C Basic electrical relationships The decibel is used extensively in electromagnetic measurements. It is the log of the ratio oftwoamplitudes.Theamplitudesareinpower,voltage,amps,electricieldunits,and magneticieldunits. decibel = dB = 10 log (P 2 /P1) Dataissometimesexpressedinvoltsorieldstrengthunits. In this case, replace P with V2 /R. If the impedances are equal, the equation becomes: dB = 20 log(V2 /V1) A unit of measure used in EMI measurements is dBµV or dBµA. The relationship of dBµV and dBm is as follows: dBµV = 107 + PdBm Thisistrueforanimpedanceof50Ω. Wavelength (l) is determined using the following relationship: λ = 3x10 8 / f (Hz) or λ = 300/f (MHz) 21 | Keysight | Making EMI Compliance Measurements - Application Note Appendix D Detectors used in EMI measurements—peak, quasi-peak, and average Peak detector Initial EMI measurements are made using the peak detector. This mode is much faster than quasi-peak, or average modes of detection. Signals are normally displayed on spectrum analyzers or EMI receivers in peak mode. Since signals measured in peak detection mode always have amplitude values equal to or higher than quasi-peak or average detection modes, it is a very easy process to take a sweep and compare the results to a limit line. If all signals fall below the limit, then the product passes, and no further testing is needed. Peak detector operation The EMI receiver has an envelope or peak detector in the IF chain with a constant time such that the voltage at the detector output follows the peak value of the IF signal at all times. In other words, the detector can follow the fastest possible changes in the envelope of the IF signal, but not the instantaneous value of the IF sine wave (see Figure D-1). Output of the envelope detector follows the peaks of the IF signal Figure D-1. Peak detector diagram 22 | Keysight | Making EMI Compliance Measurements - Application Note Appendix D (continued) Quasi-peak detector Most radiated and conducted limits are based on quasi-peak detection mode. Quasipeak detectors weigh signals according to their repetition rate, which is a way of measuring their annoyance factor. As the repetition rate increases, the quasi-peak detector does not have time to discharge as much, resulting in a higher voltage output. (See Figure D-2 below.) For continuous wave (CW) signals, the peak and the quasi-peak are the same. Since the quasi-peak detector always gives a reading less than or equal to peak detection, why not use quasi-peak detection all the time? Though quasi-peak measurements can help you more easily pass EMI compliance tests, they are much slower by 2 or 3 orders of magnitude, compared to using the peak detector. Quasi-peak detector output varies with impulse rate Peak response Quasi-peak detector reading Quasi-peak detector response t t Figure D-2. Quasi-peak detector response diagram Quasi-peak detector operation The quasi-peak detector has a charge rate much faster than the discharge rate, therefore the higher the repetition rate of the signal, the higher the output of the quasi-peak detector. The quasi-peak detector also responds to different amplitude signals in a linear fashion. High-amplitude, low-repetition rate signals could produce the same output as low-amplitude, high-repetition-rate signals. 23 | Keysight | Making EMI Compliance Measurements - Application Note Appendix D (continued) Average detector The average detector is required for some conducted emissions tests in conjunction with using the quasi-peak detector. Also, radiated emissions measurements above 1 GHz are performed using average detection. The average detector output is always less than or equal to peak detection. Average detector operation Average detection is similar in many respects to peak detection. Figure D-3 shows a signal that has just passed through the IF and is about to be detected. The output of the envelope detector is the modulation envelope. Peak detection occurs when the post detection bandwidth is wider than the resolution bandwidth. For average detection to takeplace,thepeakdetectedsignalmustpassthroughailterwithabandwidthmuch lessthantheresolutionbandwidth.Theilteraveragesthehigherfrequencycomponents, such as noise, at the output of the envelope detector. Average detection A t Envelope detector Filters Average detector Figure D-3. Average detection response diagram RMS average detector RMS average weighting receivers employ a weighting detector that is a combination of the rms detector (for pulse repetition frequencies above a corner frequency fc) and the average detector (for pulse repetition frequencies below the corner frequency fc), thus achieving a pulse response curve with the following characteristics: 10 dB/decade above the corner frequency, and 20 dB/decade below the corner frequency. See CISPR 16-1-1 2010 for detailed response characteristics. 24 | Keysight | Making EMI Compliance Measurements - Application Note Appendix E EMC regulatory agencies IEC (CISPR) IEC Central Ofice Sales Department PO Box 131 3, Rue de Verembe 1121 Geneva 20, Switzerland www.iec.ch http://www.iec.ch/standardsdev/publications/ guide.htm ITU-R (CCIR) ITU, General Secretariat, Sales Service Place de Nation 1211 Geneva, Switzerland Telephone: +41 22 730 5111 Fax: +41 22 733 7256 http://www.itu.int/ITU-R Australia Australia Electromechanical Committee Standards Association of Australia PO Box 458 North Sydney N.S.W. 2060 Telephone: +61 2 963 41 11 Fax: +61 2 963 3896 AustraliaElecto-technical Committee http://www.ihs.com.au/standards/iec/ Belgium Comite Electrotechnique Belge Boulevard A. Reyerslaan, 80 B-1030 BRUSSELS Telephone: Int +32 2 706 85 70 Fax: Int +32 2 706 85 80 http://www.bec-ceb.be Canada Standards Council of Canada Standards Sales Division 270 Albert Street, Suite 200 Ottawa, Ontario K1P 6N7 Telephone: 613 238 3222 Fax: 613 569 7808 http://www.scc.ca Canadians Standards Association (CSA) 5060 Spectrum Way Mississauga, Ontario L4W 5N6 Telephone: 416 747 4000 800 463 6727 Fax: 416 747 2473 http://www.csa.ca Denmark Dansk Elektroteknisk Komite Strandgade 36 st DK-1401 Kobenhavn K Telephone: +45 72 24 59 00 Fax: +45 72 24 59 02 http://www.en.ds.dk France Comite Electrotechnique Francais UTE CEdex 64 F-92052 Paris la Defense Telephone: +33 1 49 07 62 00 Fax: +33 1 47 78 71 98 http://www.ute-fr.com/FR Germany VDE VERLAG GmbH Bismarckstr. 33 10625 Berlin Telephone: + 49 30 34 80 01 - 0 Fax: + 49 30 341 70 93 email: [email protected] India Bureau of Indian Standards, Sales Department Manak Bhavan 9 Bahadur Shah Zafar Marg. New Delhi 110002 Telephone: + 91 11 331 01 31 Fax: + 91 11 331 40 62 http://www.bis.org.in Italy CEI-Comitato Elettrotecnico Italiano Sede di Milano Via Saccardo, 9 20134 Milano Telephone: 02 21006.226 Fax: 02 21006.222 http://www.ceiweb.it Japan Japanese Standards Association 1-24 Akasaka 4 Minato-Ku Tokyo 107 Telephone: + 81 3 583 8001 Fax: + 81 3 580 14 18 http://www.jsa.or.jp/default_english.asp 25 | Keysight | Making EMI Compliance Measurements - Application Note Appendix E (continued) EMC regulatory agencies Netherlands Nederlands Normalisatie-Instituut Afd. Verdoop en Informatie Kalfjeslaan 2, PO Box 5059 2600 GB Delft Telephone: (015) 2 690 390 Fax: (015) 2 690 190 www.nni.nl United Kingdom BSI Standards 389 Chiswick High Road London W4 4AL Telephone: +44 (0)20 8996 9001 Fax: +44 (0)20 8996 7001 www.bsi-global.com Norway Norsk Elektroteknisk Komite Harbizalleen 2A Postboks 280 Skoyen N-0212 Oslo 2 Telephone: 67 83 87 00 Fax: 67 83 87 01 https://www.standard.no/en/toppvalg/nek/ The-Norwegian-Electrotechnical-Committee/#. VDc6XO8lF7c British Defence Standards DStan Helpdesk UKDefence Standardization Room 1138 Kentigern House 65 Brown Street Glasgow G2 8EX Telephone: +44 (0) 141 224 2531 Fax: +44 (0) 141 224 2503 http://www.dstan.mod.uk United States of America America National Standards Institute Inc. Sales Dept. 1430 Broadway New York, NY 10018 Telephone: 212 642 4900 Fax: 212 302 1286 http://webstore.ansi.org South Africa South African Bureau of Standards Electronic Engineering Department Private Bag X191 Pretoria 0001 Republic of South Africa https://www.sabs.co.za Spain Comite Nacional Espanol de la CEI Francisco Gervas 3 E-28020 Madrid Telephone: + 34 91 432 60 00 Fax: + 34 91 310 45 96 http://www.aenor.es Sweden Svenska Elektriska Kommissionen PO Box 1284 S-164 28 Kista-Stockholm Telephone: 08 444 14 00 Fax: 08 444 14 30 http://www.elstandard.se/standarder/emc_standarder.asp Switzerland Swiss Electrotechnical Committee Swiss Electromechanical Association Luppmenstrasse 1 CH-8320 Fehraltorf Telephone: + 41 44 956 11 11 Fax: + 41 44 956 11 22 http://www. electrosuisse.ch/ FCC Rules and Regulations Technical Standards Branch 2025 M Street N.W. MS 1300 B4 Washington DC 20554 Telephone: 202 653 6288 http://www.fcc.gov FCC Equipment Authorization Branch 7435 Oakland Mills Road MS 1300-B2 Columbia, MD 21046 Telephone: 301 725 1585 http://www.fcc.gov 26 | Keysight | Making EMI Compliance Measurements - Application Note GlossaryofAcronymsandDeinitions Ambient level Antenna-induced voltage Decoupling network 1. The values of radiated and conducted signalandnoiseexistingataspeciiedtest location and time when the test sample is not activated. 2. Those levels of radiated and conducted signalandnoiseexistingataspeciiedtest location and time when the test sample is inoperative. Atmospherics, interference from other sources, and circuit noise, or other interference generated within the measuring set compose the ambient level. The voltage which is measured or calculated to exist across the open circuited antenna terminals. A decoupling network is an electrical circuit for preventing test signals, which are applied to the EUT interfering with other devices, equipment, or systems that are not under test. IEC 801-6 states that the coupling and decoupling network systems can be integrated in one box or they can be in separate networks. Amplitude modulation Auxiliary equipment 1. In a signal transmission system, the process, or the result of the process, where the amplitude of one electrical quantity is varied in accordance with some selected characteristic of a second quantity, which need not be electrical in nature. 2. The process by which the amplitude of a carrierwaveisvariedfollowingaspeciied law. Equipment not under test that is nevertheless indispensable for setting up all the functions and assessing the correct performance of the EUT during its exposure to the disturbance. Anechoic chamber 1. A shielded room which is lined with radio absorbingmaterialtoreducerelections from all internal surfaces. Fully lined anechoic chambers have such material on allinternalsurfaces:wall,ceiling,andloor. It'salsocalleda“fullyanechoicchamber.” A semi- anechoic chamber is a shielded room which has absorbing material on all surfacesexcepttheloor. Antenna (aerial) 1. A means for radiated or receiving radio waves. 2. A transducer which either emits radio frequency power into space from a signal source or intercepts an arriving electromagneticield,convertingitintoan electrical signal. Antenna terminal conducted interference Any undesired voltage or current generated within a receiver, transmitter, or associated equipment appearing at the antenna terminals. Balun A balun is an antenna balancing device, which facilitates use of coaxial feeds with symmetrical antennae, such as a dipole. Broadband emission Broadbandisthedeinitionforaninterference amplitude when several spectral linesarewithintheRFIreceiver'sspeciied bandwidth. Broadband interference (measurements) A disturbance that has a spectral energy distributionsuficientlybroad,sothatthe response of the measuring receiver in use doesnotvarysigniicantlywhentunedover aspeciiednumberofreceiverbandwidths. Conducted interference 1. An antenna consisting of a straight conductor, usually not more than a half-wavelength long, divided at its electrical center for connection to a transmission line. 2. Any one of a class of antennas producing a radiation pattern approximating hat of an elementary electric dipole. Electromagnetic compatibility (EMC) 1. The capability of electronic equipment systemstobeoperatedwithindeined margins of safety in the intended operational environment atdesignedlevelsofeficiency without degradation due to interference. 2. EMC is the ability of equipment to function satisfactorily in its electromagnetic environment without introducing intolerable disturbances into that environment or into other equipment. Electromagnetic interference Electromagnetic interference is the impairment of a wanted electromagnetic signal by an electromagnetic disturbance. Electromagnetic wave Interference resulting from conducted radio noise or unwanted signals entering a transducer (receiver) by direct coupling. The radiant energy produced by the oscillation of an electric charge characterized by oscillation of the electric and magnetic ields. Cross coupling Emission The coupling of a signal from one channel, circuit, or conductor to another, where it becomes an undesired signal. Electromagnetic energy propagated from a source by radiation or conduction. Antenna factor The factor which, when properly applied to the voltage at the input terminals of the measuring instrument, yields the electric ieldstrengthinvoltspermeteranda magneticieldstrengthinamperesper meter. Dipole 27 | Keysight | Making EMI Compliance Measurements - Application Note GlossaryofAcronymsandDeinitions Farield Open area Stripline Theregionwherethepowerluxdensity from an antenna approximately obeys an inverse squares law of the distance. For a dipole, this corresponds to distances greater than l/2 where l is the wavelength of the radiation. A site for radiated electromagnetic interference measurements which is open latterrainatadistancefarenoughaway from buildings, electric lines, fences, trees, underground cables, and pipe lines so that effects due to these factors are negligible. Thissiteshouldhaveasuficiently low level of ambient interference to permit testing to the required limits. Parallel plate transmission line to generateanelectromagneticieldfortesting purposes. Ground plane 1. A conducting surface of plate used as a common reference point for circuit returns and electric or signal potentials. 2. A metal sheet or plate used as a common reference point for circuit returns and electrical or signal potentials. Polarization A term used to describe the orientation of theieldvectorofaradiatedield. Immunity Radiated interference 1. The property of a receiver or any other equipment or system enabling it to reject a radio disturbance. 2. The ability of electronic equipment to withstand radiated electromagnetic ieldswithoutproducingundesirable responses. Radio interference resulting from radiated noise of unwanted signals. Compare radio frequency interference. Intermodulation Mixing of two or more signals in a nonlinear element, producing signals at frequencies equal to the sums and differences of integral multiples of the original signals. Radiation The emission of energy in the form of electromagnetic waves. Radio frequency interference RFI is the high-frequency interference with radio reception. This occurs when undesired electromagnetic oscillations indentrancetothehigh-frequencyinput of a receiver or antenna system. Isotropic Having properties of equal values in all directions. Monopole An antenna consisting of a straight conductor, usually not more than onequarter wavelength long, mounted immediately above, and normal to, a ground plane. It is connected to a transmissions line at its base and behaves, with its image, like a dipole. Narrowband emission That which has its principal spectral energy lying within the bandpass of the measuring receiver in use. RFI sources Equipment and systems as well as their components which can cause RFI. Shielded enclosure A screened or solid metal housing designed expressly for the purpose of isolating the internal from the external electromagnetic environment. The purpose is to prevent outside ambient electromagneticieldsfromcausing performance degradation as well as prevent emissions from causing interference to outside activities. Susceptibility The characteristic of electronic equipment that permits undesirable responses when subjected to electromagnetic energy. 28 | Keysight | Making EMI Compliance Measurements - Application Note myKeysight www.keysight.com/find/mykeysight A personalized view into the information most relevant to you. www.lxistandard.org LAN eXtensions for Instruments puts the power of Ethernet and the Web inside your test systems. Keysight is a founding member of the LXI consortium. Keysight Assurance Plans www.keysight.com/find/AssurancePlans Up to five years of protection and no budgetary surprises to ensure your instruments are operating to specification so you can rely on accurate measurements. www.keysight.com/go/quality Keysight Technologies, Inc. DEKRA Certified ISO 9001:2008 Quality Management System Keysight Channel Partners www.keysight.com/find/channelpartners Get the best of both worlds: Keysight’s measurement expertise and product breadth, combined with channel partner convenience. www.keysight.com/find/mxe For more information on Keysight Technologies’ products, applications or services, please contact your local Keysight office. The complete list is available at: www.keysight.com/find/contactus Americas Canada Brazil Mexico United States (877) 894 4414 55 11 3351 7010 001 800 254 2440 (800) 829 4444 AsiaPaciic Australia China Hong Kong India Japan Korea Malaysia Singapore Taiwan Other AP Countries 1 800 629 485 800 810 0189 800 938 693 1 800 11 2626 0120 (421) 345 080 769 0800 1 800 888 848 1 800 375 8100 0800 047 866 (65) 6375 8100 Europe & Middle East Austria Belgium Finland France Germany Ireland Israel Italy Luxembourg Netherlands Russia Spain Sweden Switzerland United Kingdom 0800 001122 0800 58580 0800 523252 0805 980333 0800 6270999 1800 832700 1 809 343051 800 599100 +32 800 58580 0800 0233200 8800 5009286 800 000154 0200 882255 0800 805353 Opt. 1 (DE) Opt. 2 (FR) Opt. 3 (IT) 0800 0260637 For other unlisted countries: www.keysight.com/find/contactus (BP-04-23-15) This information is subject to change without notice. © Keysight Technologies, 2007-2015 Published in USA, July 25, 2015 5990-7420EN www.keysight.com
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