EMC Back to Basics. Matthew Carter EMC Product Support Engineer Agilent Technologies Inc. April 16, 2014

EMC Back to Basics Matthew Carter EMC Product Support Engineer Agilent Technologies Inc. April 16, 2014 Agilent Technologies, Inc. 2014

Agenda EMC Back to Basics Overview What is Electromagnetic Compatibility? Which equipment? Pre-compliance vs. Compliance Which standards? EMI Receiver Architecture Specifications: Which are important and why? Making an Emissions Measurement Other equipment considerations Q&A 4

Sources of Electromagnetic Interference Natural Sources -Lightning -Sun Spots Unintentional emitting products -Power lines -Motors (mixers, hair dryers etc) -Lighting, appliances Devices that intentionally emit signals -Most computers -Hand held communication devices -Radar, transceivers, broadcast equipment etc 5

Basic Definitions Electromagnetic Compatibility (EMC): The ability for electrical devices to operating in the same environment without interfering with one another Electromagnetic Interference (EMI): Electromagnetic energy emissions from one device causing reduced or degraded performance in another device Electromagnetic Compliance A product is considered to be in Electromagnetic Compliance when it meets all applicable electromagnetic regulations. 6

EMC Market Overview Global market, mandatory regulation Vendors test in order to be able to sell their products Electronic Smog testing Commercial Standards determined by International Committee Slow moving, political Adaptive Adapt techniques and measurements to meet the needs of rapidly changing products Eg: IT, Cellular, Wireless, Multimedia 7

EMC Market Segmentation Measurement Type: Emissions Radiated & Conducted - Compliance - Pre-Compliance Immunity Radiated & Conducted Compliance Application: Commercial Military Sub-segments: - Product Type - Product Class - Country -. 8

Definitions: Emissions, Susceptibility, Immunity Radiated Emissions Radiated Susceptibility (or Immunity) Conducted Emissions Conducted Susceptibility (or Immunity)

transducer Measurement Equipment Emissions Radiated Emissions Conducted Emissions EUT EUT Mains Compliance receivers Spectrum Analyzers Preamps Antennas Measurement SW Towers Turntables Control SW Equipment Artificial Mains Networks LISN - (line impedance stabilization network) Conducted Transducers Measurement SW Open Sites Anechoic Chambers Semi-Anechoic Chambers TEM cells Reverberation chambers

Compliance vs. Precompliance Measurements Full Compliance - Pass/Fail final regulatory testing - Requires specific equipment and test site - must comply to specific Mil or Comm l standards MXE - Expensive and time consuming Precompliance Measurements - Unofficial performance estimate done prior to Full Compliance test - Typically done with SA on available location - Purpose is to minimize chance of failure at Compliance test. X-Series w/ N6141A

transducer ESD source Measurement Equipment Immunity Radiated Immunity Conducted Immunity ~ ~ EUT EUT AMN transducer RF Sources Power meters Power amps Antennas Measurement SW Control SW Equipment LISN Coupling Transducers - clamps, etc. ESD sources Screen rooms TEM cells GTEM cells

Segmentation Measurement Type: Emissions Radiated & Conducted - Compliance - Pre-Compliance Immunity Radiated & Conducted Compliance Application: Commercial Military Sub-segments: - Product Type - Product Class - Country -.

CISPR Recommends Commercial Limits, Measuring Equipment and Methodologies CISPR (Special International Committee on Radio Interference) a sub committee of the IEC (International Electrotechnical Commission) determines and recommends required emissions and immunity: - limits for products sold in the worldwide commercial market - test equipment requirements - test procedures/methodologies

CISPR Product Groups CISPR 11 - Industrial, Scientific, and Medical (ISM) Radio-Frequency Equipment CISPR 12 - Vehicles, Motorboats, and Spark-Ignited Engine-Driven Devices CISPR 13 - Sound and Television Broadcast Receivers and Associated Equipment CISPR 14 - Household Appliances, Electric Tools, and Similar Apparatus CISPR 15 - Electrical Lighting and Similar Equipment. CISPR 17 - Suppression Characteristics of Passive Radio Interference Filters and Suppression Components. CISPR 18 - Overhead Power Lines and High-Voltage Equipment CISPR 20 - Sound and Television Broadcast Receivers and Associated Equipment CISPR 21 - Interference to Mobile Radio communications CISPR 22 - Information Technology Equipment Radio Disturbance Characteristics CISPR 24 - Information Technology Equipment Immunity Characteristics CISPR 25 - Receivers Used on Board Vehicles, Boats, and on CISPR 32 Multimedia devices emission testing (under development) CISPR 35 Multimedia devices immunity testing (under development)

Commercial requirements for EMI receivers What is CISPR 16-1-1? Specifies the characteristics and performance of equipment for the measurement of radio disturbance in the frequency range 9 khz to 18 GHz for commercial devices. CISPR 16 Equipment Requirements Detectors (Peak, Quasi-peak, EMI-avg, etc) Reference BW (aka. RBW filter) Amplitude Accuracy Input Impedance Ability to pass the CISPR pulse test And more

Commercial Regulations IEC/CISPR Measurement Std. CISPR 16 Equipment Std. CISPR 16 Product Std. - CISPR 11-15, etc. IEC 61XXX GB VCCI ANSI FCC CENELEC EN

Commercial EMC Standards - Examples Country /Organization Entity Standards US FCC, DoD FCC Part xx, MIL-STD. xxx IEC CISPR CISPR Pub. xx IEC TC77 IEC 6xxxx EC CENELEC EN 550xx Canada CSA ICES xxx Australia/NZ AS/NZS AS/NZS CISPR xx Japan VCCI J550xx China (Mainland) Korea Taiwan CCC, MoD MIC BSMI GB xxxx- xxxx GJB xxx- xx (equivalent to Mil-STD) Equivalent to EN 550xx CNS xxxx

Segmentation Measurement Type: Emissions Radiated & Conducted - Compliance - Pre-Compliance Immunity Radiated & Conducted Compliance Application: Commercial Military Sub-segments: - Product Type - Product Class - Country -.

Country-Specific Military Regulations Tend to be based on US MIL STD 461.. Current version: 461F (2007) but many include unique emissions and immunity tests

MIL-STD 461 Receiver Requirements U.S. military standard Published by the Department of Defense MIL-STD-461 Section 4.3.10 Receiver Requirements Peak detector Sensitivity Amplitude accuracy Frequency accuracy Specified dwell times

Agenda EMC Back to Basics Overview EMI Receiver Architecture Specifications: Which are important and why? Making an Emissions Measurement Other equipment considerations Q&A 22

EMI Receiver Block Diagram Input 2 Pre-amp MXE Input 1 Transient Limiter Attenuation RF Preselector Digital IF Filter Digital Detectors FFT Analog IF Filter Swept vs. FFT Digital Log Amp ADC 23

RF Preselector Bands 24

RF Pre-selection (RF input filtering) Purpose of RF pre-selection Help to prevent overload by reducing total energy at input mixer RF preselector tracks the center frequency of the EMI receiver The bandwidth of the RF preselector is wider than the widest RBW used Useful in measuring broadband signals Types of filters used in RF pre-selectors Low-pass, Band-pass and High-pass Fixed and Tracking Narrow band signals Broadband signals RF Preselector 25

EMI Receiver Block Diagram Input 2 Pre-amp MXE Input 1 Transient Limiter Attenuation RF Preselector Digital IF Filter Digital Detectors FFT Analog IF Filter Swept vs. FFT Digital Log Amp ADC 26

Methods to EMI Scanning Stepped Scan Slowest method LO moves for every bin Must re-tune LO each time Swept Scan Slow (slightly faster than Stepped) LO re-tunes once each sweep FFT Time Domain Scan (TDS) Very fast Highly overlapped FFT (>90%) Alternate scan method allowed by CISPR 16 27

amplitude amplitude How Time Domain Sweep Saves Time Have to dwell at each RBW Receiver Resolution BW Only have to dwell for each FFT BW (multiple RBWs) Receiver FFT BW frequency Swept or Stepped Frequency Scan Time Domain Frequency Scan frequency 28

Agenda EMC Back to Basics Overview EMI Receiver Architecture Specifications: Which are important and why? Making an Emissions Measurement Other equipment considerations Q&A 29

Specifications? A Definition Specifications describe the performance of parameters covered by the product warranty (temperature = 5 to 55 C, unless otherwise noted). Typical values describe additional product performance information that is not covered by the product warranty. It is performance beyond specification that 80 % of the units exhibit with a 95 % confidence level over the temperature range 20 to 30 C. Typical performance does not include measurement uncertainty. Nominal values indicate expected performance, or describe product performance that is useful in the application of the product, but is not covered by the product warranty. 30

Key Specifications for EMI Sensitivity Amplitude Accuracy Scan Speed Others? 31

Specifications: Sensitivity/DANL Sensitivity is the Smallest Signal That Can Be Measured Signal Equals Noise 2.2 db 36

Specifications: Sensitivity/DANL Effective Level of Displayed Noise is a Function of RF Input Attenuation signal level 10 db Attenuation = 10 db Attenuation = 20 db Signal To Noise Ratio Decreases as RF Input Attenuation is Increased 37

Sensitivity/DANL: IF Filter (RBW) Displayed Noise is a Function of IF Filter Bandwidth 100 khz RBW 10 db 10 db 10 khz RBW 1 khz RBW Decreased BW = Decreased Noise 38

Sensitivity/DANL: Summary For Best Sensitivity Use: Narrowest Resolution BW allowed Minimum RF Input Attenuation Sufficient Averaging (video or trace - if allowed) Using the Preamp also improves sensitivity Noise Floor Extension 41

Specifications: Amplitude Accuracy Components which contribute to uncertainty are: Input mismatch (VSWR) RF Input attenuator (Atten. switching uncertainty) Mixer and input filter (frequency response) IF gain/attenuation (reference level accuracy) RBW filters (RBW switching uncertainty) Log amp (display scale fidelity) Calibrator (amplitude accuracy) FFT 25

Digital IF Improves Amplitude Accuracy Input Connector RF Input Attenuator 2 db Steps Pre-selector Downconversion ADC DSP Input connector (mismatch) Calibrator RF input attenuator flatness and switching Mixer and input filter frequency response Frequency Dependent Frequency Independent Digital IF improves Amplitude Accuracy: Ref Level switching uncertainty (IF gain) Level correction digitally synthesized RBW filter switching uncertainty RBWs all digitally synthesized Display scale fidelity (Log Amp) Log response & display scaling digitally synthesized IF Filter IF Gain Log Amp Video Filter Log ADC 37

Digital IF Improves Amplitude Accuracy Input Connector RF Input Attenuator 2 db Steps Pre-selector Downconversion ADC DSP Amplitude Uncertainty Ref Level Switching RBW Switching Display Scale Fidelity N9038A Receiver 0dB Frequency Dependent Analog IF (older receivers) <= +/- 1dB +/-.05dB <= +/-.5dB +/-.15dB <= +/-.85dB Frequency Independent Digital IF improves Amplitude Accuracy: Ref Level switching uncertainty (IF gain) Level correction digitally synthesized RBW filter switching uncertainty RBWs all digitally synthesized Display scale fidelity (Log Amp) Log response & display scaling digitally synthesized IF Filter IF Gain Log Amp Video Filter Log ADC 38

Specifications: Scan Speed Need for SPEED DUTs that require short measurement time (ex. motor starter) Test MORE devices Shorter turn-around-time Depends On: Scan type (Stepped, Swept, Time Domain) Resolution Bandwidth Dwell Time RF Preselector Other? 39

Agenda EMC Back to Basics Overview EMI Receiver Architecture Specifications: Which are important and why? Making an Emissions Measurement Other equipment considerations Q&A 40

Making an emissions measurement Recommended by CISPR Measurement methodology found in CISPR 16-2-3 Fastest way to make the measurement MIL Measurements* Pre-scan Data Reduction Maximization Final Measurement Report Generation 41

Pre-Scan Preview spectrum using Peak detector Measurement Parameters Prescan Frequency range Limit lines Margins Antenna Factors Scan Type Scan Types Stepped Swept Time Domain Pre-scan Data Reduction Maximization Final Measurement Report Generation 42

Data Reduction Signals exceeding the limit are automatically: Marked in red Peaks are marked with white X Added to signal list Only do final measurement on signals exceeding the limit and margin Don t measure unnecessary signals Saves time Signal List Pre-scan Data Reduction Maximization Final Measurement Report Generation 43

Maximization Techniques Maximize signal amplitude before final measurement Receiver mode Spectrum Analyzer Mode Monitor Spectrum Simultaneous spectrum and meter measurements Access to signal (suspect) list Meter max hold Spectrum Analyzer mode Switch between EMI receiver and SA modes using global center frequency Powerful analyzer mode Pre-scan Data Reduction Maximization Final Measurement Report Generation 44

Final Measurement Signals in list are automatically measured Measure suspect signals with Quasi-peak, EMI average detector, etc. Suspect signals still failing? Start troubleshooting? Pre-scan Data Reduction Maximization Final Measurement Report Generation 45

Report Generation Report Generator Settings Screenshots Tables Report Format: PDF or HTML Pre-scan Data Reduction Maximization Final Measurement Report Generation 46

Agenda EMC Back to Basics Overview EMI Receiver Architecture Specifications: Which are important and why? Making an Emissions Measurement Other equipment considerations Q&A 47

Transducers for EMI measurements a device that receives a signal in the form of one type of energy and converts it to a signal in another form Near Field Probe Near Field Scanner Line Impedance Stabilization Network (LISN) Antennas Other devices? -dictionary.com 48

Near Field Probes E & H Field Use Cases Pre-compliance Diagnostics Characteristics E Field Probe Frequency Range Spatial Resolution Sensitivity Measure or Generate Fields Emissions or Susceptibility H Field Probe 49

Near Field Scanners 50

LISN: Line Impedance Stabilization Network Typically used for conducted emission measurements Isolates the power mains from the EUT Isolates EUT from the power mains Powers the EUT and couples signals to EMI receiver No Transient Limiter Required Power Mains MXE Receiver EUT LISN Types of LISNs V-LISN Delta LISN T-LISN 51

EMI Broadband Antenna Examples Double ridged horn Biconical Log Periodic Hybrid Log Periodic Hybrid Log Periodic 52

Antenna Factor (db/m) Understanding Antenna Factors Ratio of the electric field to the voltage out of the antenna Linear Units AF = E in V out 20 Typical biconical antenna factors AF = Antenna Factor (1/m) E = Electric Field units (V/m) V = Voltage output from antenna (V) 10 Log Units AF(dB/m) = E(dBµV/m) V(dBµV) 20 150 300 Frequency (MHz) 53

Antenna Factors on a Typical Display Corrected for a broadband antenna 54

Examples of Test Facilities 5 Meter Semi Anechoic* Chamber (Located on the Agilent Santa Rosa site) This chamber uses 2 antenna towers, one for vertical and one for horizontal polarization. Origin Anechoic an- not + echoic (echo) *Anechoic material is made of carbon impregnated rubberized cones or ferrite tiles or both 55

Examples of Test Facilities Open Area Test Site (OATS) Useful in low ambient signal environments Reverberation Chamber Uses a mode stirring tuner to generate a uniform field (no absorption material on the walls) GHz Transverse Electro Magnetic Cell (GTEM Cell) Used for smaller devices. Can be used for immunity and emissions. 56

Automation Software Reasons for Automation -Supplement skill and knowledge of the tester -Measurements repeatability -Results are presented in a common format -Reduce test time by automating setups -Run turntables and antenna towers Types of Automation -Internally executed application such as N6141A EMI Application -PC based applications Software Available 57

Automation Software Receiver Control Room Automation software typically communicates with the receiver over LAN or GPIB Chamber Uses SCPI commands 58

Questions? Please type them in the chat box now N9038A MXE EMI Receiver www.agilent.com/find/mxe X-Series Signal/Spectrum Analyzers www.agilent.com/find/x-series 59