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Glossary of terms | EMC Test Equipment

Welcome to the AMETEK CTS EMC Test Equipment Glossary
Something missing? Feel free to post a suggestion for a term that should be included on this page. You can even suggest a definition.

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  • A

    • Anechoic Chamber

      In EMC, a well-shielded room designed to reduce reflections of electromagnetic waves and isolate the test setup from spurious influences. A fully anechoic chamber aims to absorb electromagnetic waves from all directions using RF absorbing materials while a semi-anechoic chamber (SAC) usually leaves the floor a bare, conductive metal material.

    • Arbitrary Waveform Generator - AWG

      A piece of electronic test equipment that can generate very complex waveforms.  Contrary to a signal generator or function generator, AWGs usually contain much more memory to store the complex waveform digitally.

    • Artificial Mains Network - AMN

      Artificial Network (AN) – A device that can facilitate interaction between electrical systems and components, and often simulates the impedance of the real-world application or power.

    • Artificial Mains Network-AMN
      A type of artificial network (AN) meant to be used with mains power to a DUT.
    • Atmospheric discharges such as lightning

      Lightning strokes into high voltage power distribution systems are causing transients in low voltage power mains networks. Via coupling these transients can also be detected in data bus systems, I/O lines and any cabling in the industrial area.

      Parameters : Range of voltage some tens of kilovolts, range of current some tens of kilo amps, high-energy pulses with rise times in the microsecond range.

      Standard reference : IEC/EN 61000-4-5 

    • Auxiliary Equipment - AE

      Any subassembly or subsystem that is meant to be used with the DUT and supports testing of the main DUT, either by being a power or signal input, output, or load. An AE may be the real subassembly used in the application or simulated for the lab.

  • B

    • Bandwidth

      The usable frequency range of a programmable source, or amplifier.  For RF amplifiers bandwidth is defined as the difference between the upper and lower frequency of operation (f2 - f1). For voltage sources, this is typically defined as the frequency where a -3 dB reduction in output signal compared to the nominal signal and normally starts at DC.  Only signals within the frequency range of the operational bandwidth will be correctly amplified.

    • Bonded/Bonding
      Low resistance electrical connection, typically between conductive parts of a test setup
    • Bulk Current Injection - BCI

      A type of conducted immunity test, mostly in the higher frequency ranges to ensure compliance and product reliability requirements.  Typically used to simulate unintended nearby electrical disturbance that may be unintentionally coupled on the wires and cables.

    • Burst
      In EMC, an electrical fast transient is a series of fast voltage spikes simulating nearby electrical problems commonly caused by switching events or repetitive, fast current changes in inductive loads.

  • C

    • Calibration
      In metrology and EMC, a regularly-performed method of ensuring the accuracy and repeatability of a source, quantity, measurement system or process. Accredited calibrations are designed to withstand the rigor of audits through process, documentation and method and can trace their accuracy back to a reference standard.
    • Capacitive Coupling Clamp
      A type of clamp used for immunity testing of cables or harnesses to induce a voltage from the immunity source to the EUT and its associated wiring where galvanic isolation is preferred to direct connection.
    • Closed Loop
      In EMC, a type of ‘live’ test where the input is adjusted based on measured values to achieve an exact test level with the DUT.
    • Combination Wave Generator
      A type of standard pulse generator that generates short voltage/current spikes on wiring. Combination Wave Generators usually provide multiple types of pulses, grouped together based on similar standard requirements.
    • Conducted
      In EMC, disturbances transferred on wires, cables, or conductive material.
    • Coupling
      In EMC, the transfer of electrical energy from the immunity disturbance simulator to the DUT/EUT. Ensuring that the simulated disturbance is routed to the line that is intended when performing immunity tests.
    • Coupling/Decoupling Network - CDN
      A device that both couples and decouples a DUT to/from the source of the simulated immunity testing.  This typically involves a defined R/L/C combination defined in the standard and may serve to also simulate the impedance of the real-world power source and associated cabling.
    • Current Injection Probe
      A type of probe, used to couple large RF currents onto conductors.  These usually use induction coupling.

  • D

    • Decoupling
      Isolating the simulated disturbance from unintended lines of other equipment connected, or near to the test setup.
    • Device Under Test - DUT
      Commonly refers to a standalone discreet test sample during immunity or emissions testing. Often used interchangeably with EUT.
    • Differential Probe
      Used to measure differential signals, usually with an oscilloscope, but have an additional advantage that they can be used when no additional ground should be applied to the test setup, thus avoiding ground loops, and bypassing any necessary test or coupling electronics on the negative line.
    • Dips and Drops
       In EMC, a type of immunity test. A dip is a reduction of the nominal power supply voltage, but a drop usually simulates total loss of power.
    • Directional Coupler
      In EMC, typically ensures that RF energy is transmitted only in one direction in the test setup.  Often used to monitor reverse power using a power meter.

  • E

    • Electrical Fast Transient - EFT
      A series of fast voltage spikes simulating a nearby electrical problems commonly caused by switching events or repetitive, fast current changes in inductive loads.
    • Electrical/Electronic Subassembly - ESA
      In automotive EMC, a term used to define a separate unit of technical electrical or electronic equipment that are type tested separately for both emissions and immunity before being integrated in a final vehicle.
    • Electromagnet Compatibility - EMC
      Compatibility between devices in the same electromagnetic environment, ensuring that electrical and electronic devices and systems do not disturb other devices through intended or unintended electromagnetic emissions, and remain immune to other devices emissions.
    • Electromagnetic Interference - EMI
      Interference from intended or unwanted electromagnetic sources.
    • Electrostatic Discharge - ESD
      ESD is a sudden and momentary flow of electric current between two electrically charged objects caused by contact, or dielectric breakdown. In EMC, one of the only immunity test classes that does not have a corresponding emissions test because the cause is either the consumer, operator or assembly process.
    • Electrostatic discharge (Old)

      ESD occurs when the static electric field between two objects exceeds the dielectric strength of the air between them. The discharge is a complex event involving a local transfer of charge at the point of discharge, electromagnetic near field coupling between the objects involved, induced current flow in the object receiving the discharge and radiated electromagnetic energy from the charged object as well as from the arc of the discharge. All of these phenomenon are capable of causing malfunctions and, in some cases, damage in electronic equipment.

      Parameters : The major effects are generated by the discharge current (< 100A) and voltage (< 30kV) with rise times in the nanosecond and even in the picosecond range.

      Standard reference : IEC/EN 61000-4-2 

    • EM Clamp
      Clamps onto the desired conductor or harness for the injection of a simulated disturbance. Typically used in the 150kHz to 230 MHz range.
    • Emissions
      In EMC, a measurement in controlled laboratory conditions of the radiated and conducted emissions of a piece of equipment to ensure that its unintended emissions do not exceed those allowed by the authorities. While most electronics and electrical equipment emit somewhat, unregulated emissions can disturb the proper function of nearby electronics and equipment.
    • Equipment Under Test - EUT
      Commonly refers to a collection of connected devices, or subsystems, during an immunity or emissions test setup.
    • ESD Gun/Simulator
      A handheld generator designed to simulate electrostatic discharge in a repeatable way in a laboratory environment during ESD immunity testing.

  • F

    • Fall off
      Fall off refers to the frequency range outside of the amplifiers specified operational bandwidth as amplification performance rolls off to 0dB.
    • Flicker
      In EMC, a voltage fluctuation that is caused by repetitive current consumption on power lines that can sum to become a source of a disturbance on the power grid.
    • Foldback
      Foldback is the protection method some amplifier designs use when the maximum specified level of reflected power is detected at the amplifiers RF output. At this point, the amplifier will protect itself by attenuating the input signal to ensure the output power cannot be increased. This action prevents the output power from increasing and the resulting reflected power from exceeding the specified limit.
    • Four-quadrant Source
      A type of bipolar power source, usually a linear power amplifier, that provides both voltage and current to the DUT, but can also accept voltage and current returns from the DUT.  Thus, the four “quadrants” of the performance envelope are +V, +I, -V and -I.
    • Fully Complaint
      A test designed, calibrated, and documented with sufficient rigor to withstand scrutiny of a regulator or auditor and exacting repeatability requirements.
    • Functional Performance Status Classification - FPSC
      A method, whereby a DUT with a more important function will have to perform better at an equal or more severe test level, compared to other DUTs of lower importance.  For example, it may be acceptable for audible pops or buzzing to occur at a higher test level in an infotainment system but must perform inside its designed specification at a lower test level.  However, the ABS system might be required to perform without error at all test levels. An FPSC may also include details like if the DUT experiences any errors at a defined test level, must it return to normal after completion of the immunity test on its own or if an operator intervention (reset) also permitted.

  • G

    • Gain
      In RF amplifiers, gain is the ratio of output power to input power.
    • Ground shift tests

      Ground shift tests are immunity tests whereby potential interference from conducted noise along a ESC’s power and signal grounds. This could be caused by faulty earthing or other coupling methods. One method usually used is coupling via a transformer, but the individual standards must be consulted to determine the recommended method. The NSG 5600 contains the necessary transformer.

  • H

    • Harmonic Current Emission (Old)

      With an increasing number of electronic power supplies used in a wide range of products the aim to limit the harmonic current emission has become more and more important. It is a specific interest of the power distribution companies to keep the harmonic current emission to a considerable low level as harmonic current causes unnecessary loading of the power distribution infrastructure. This again may affect both quality and reliability of the power supply.

      Parameters : Harmonic currents are measured up to the 40th harmonic of the fundamental. Limits for each harmonic are specified depending on the type of product.

      Standard reference : IEC/EN 61000-3-2, IEC/EN 61000-3-12 

    • Harmonics
      In EMC, typically sinusoidal currents equal to an integer multiple of the fundamental 50/60 Hz power lines that can sum from multiple sources to become a cause of a disturbance on the power grid.

  • I

    • Immunity
      In EMC, immunity to a potential electromagnetic disturbance, typically simulated in controlled, laboratory conditions, called ‘immunity testing’.
    • Inrush Current
      An initial, unusually high peak current that typically occurs when the equipment is first energized, or a particularly high power is generated, or load applied.
    • Interruptions
      In EMC, an immunity test featuring brief loss of power or signals in a test setup.
    • Inverter noise (Old)

      Depending on the coupling path, inverter noise can manifest itself in ripple on the power to certain DUTs that may be susceptible the the disturbance.

  • L

    • Lightning strikes

      Lightning strikes into high voltage power distribution systems are causing transients in low voltage power mains networks. Via coupling these transients can also be detected in data bus systems, I/O lines and any cabling in the industrial area.

      Parameters : Range of voltage some tens of kilovolts, range of current some tens of kilo amps, high-energy pulses with rise times in the microsecond range.

      Standard reference : IEC/EN 61000-4-5 

    • Line
      In EMC, this usually means a conductor, wire, or cable.

  • M

    • Magnetic Field Testing
      An immunity test to ensure that a DUT is not susceptible to nearby low frequency magnet fields, typically performed by applying current to one or two coils of wire and placing the coils near to the DUT. As most sources are voltage sources, a precise knowledge of the impedance of the coil(s) must be known to match the source to the coil for the best resolution and field strength.
    • Micropulse
      In EMC, a colloquialism for double-exponential voltage pulse from an immunity pulse generator in the microsecond or low millisecond range. 
    • Modulation
      The process of superimposing a lower-frequency signal on a higher frequency carrier wave. In EMC, AM (Amplitude Modulation) is the most common modulation.

  • O

    • Open Area Test Site - OATS
      A flat piece of usually remote land, free from unwanted reflections and external signals that could affect the results featuring a perfectly reflective ground plane.  OATS can be used for both emissions and immunity testing of large equipment.