New EMC requirements for commercial avionics: RTCA/DO-160F

The test levels, requirements, and procedures are intended to reflect the "state-of-the-art" in aviation technology and EMC testing methodology.

By: Erik J. Borgstrom, Environ Laboratories LLC

RTCA/DO-160F, Environmental Conditions and Test Procedures for Airborne Equipment, prepared by RTCA Special Committee 135, was issued on December 6, 2007, superseding the previous version, DO-160E.^[1] DO-160F covers standard procedures and environmental test criteria for testing airborne electrical and electronic equipment (avionics). The tests specified in DO-160F are typically performed to meet Federal Aviation Administration (FAA) or other international regulations covering the equipment that is installed on commercial aircraft.

The tests and test levels/limits (also referred to as "Equipment Categories") found in DO-160F are applicable to virtually every type of aircraft in use today, including small general aviation aircraft, business jets, helicopters, regional jets, and "Jumbo Jets" such as the newest airliners from Airbus (the A380) and Boeing (the 787).The document includes 26 sections and three Appendices, but it is Sections 15 through 23 and also Section 25 that cover EMC. Other examples of tests covered in DO-160F are: temperature; altitude; vibration; sand/dust; power input; radio frequency susceptibility; lightning; and electrostatic discharge.

The creation and revision of DO-160F is coordinated with the European Union version of RTCA, EUROCAE. As a result of this trans-Atlantic cooperation and joint effort by the two organizations, RTCA/DO-160F and its European twin, EUROCAE/ED-14F, are identically worded. The purpose of this article is to provide an overview of each of the sections that deal with EMC in DO-160F. Changes in each section since the release of DO-160E will also be summarized; and finally, we will take a look into the "crystal ball" to speculate on the nature of future revisions to DO-160.

SECTIONS 1-3
The first three sections cover the Purpose and Applicability (Section 1) of DO-160, provide a Definition of Terms (Section 2) used throughout the document, and give Conditions of Tests (Section 3). These first three sections are referenced in all of the subsequent sections of DO-160 and provide the general information and guidance needed for performing the specified tests accurately.

What's New for DO-160F?

• In Section 2, additional guidance covering "Applicability of Test Results".
• In Section 3, additional guidance covering "EUT Configuration for Susceptibility Tests".

SECTION 15: MAGNETIC EFFECT
This "MC" (for "Magnetic Compatibility" as opposed to "EMC" for Electromagnetic Compatibility) test is performed to determine to what extent the equipment-under-test (EUT) will deflect a compass needle, or will affect the indication from a compass sensor, also known as a "Flux Gate".

A standard compass that has a large enough dial to read one degree of needle deflection is the only test equipment required. The EUT is simply moved closer to the compass on an East-West line until one degree of deflection away from magnetic North is observed. The separation distance is then measured and the "Equipment Category" is determined.

Equipment Classes
There are five equipment categories (Y, Z, A, B, and C) that apply to installation separation distances between the EUT and compass (or compass sensor) of less than 30 centimeters to more than 300 centimeters.

What's New for DO-160F?

• New Category Y for 0 to 30 cm installation separation distance.
• Much needed descriptions of each equipment category has been added to Section 15.1 "Purpose of Test" along with a discussion of how the test results are used to determine how close the EUT may be installed to a compass (or compass sensor).
• The use of an "equivalent magnetic sensor" was added, to allow for the use of electronic compasses as opposed to the typical "free magnet" compass.

SECTION 16: POWER INPUT
Although an argument can be made that "Power Input" (or "Power Quality" as they are referred to in other standards) tests are not truly EMC tests, they are included here for two reasons. First, power/input/quality tests are often performed in the EMC lab by EMC test personnel. Second, in the latest versions of DO-160, the frequency ranges for some of the tests fall well within the parameters of typical EMC tests, and the test equipment used is similar to that used in many other "true" EMC tests found elsewhere in DO-160 and other EMC standards.

The tests in Section 16 are performed to determine that the EUT can operate as required during all of the different conditions of AC and/or DC power variations that occur during normal and emergency aircraft operation. In addition, Section 16 includes tests to verify that the EUT does not have a negative influence on the aircraft power system that would be harmful or would otherwise cause degraded performance in other installed equipment.

One interesting note about Section 16 is the fact that it is now the only section of DO-160 that contains requirements and tests that cover both the susceptibility of the EUT (such as surge, dropout, frequency transients, etc.), and the generation of harmful interference (emissions) from the EUT (such as current harmonics, re-generated energy, power factor, etc.).This fact, along with the increasing complexity and variety of modern aircraft power systems, and the sheer size of Section 16 (61 pages in DO-160F), has spurred some discussion on SC-135 about the possibility of spinning off the power input/quality requirements into a completely different document--although no immediate change is currently under consideration.

To keep pace with the "state-of-the-art" in aircraft power system design, Section 16 has seen dramatic changes over the last decade. With the new power systems in use on the newest transport aircraft, the changes made for DO-160F are quite extensive.

Change 2 to DO-160D, issued June 12, 2001, revised Section 16 fairly dramatically, by including new tests, and modifications to existing testing, to address the issues of AC harmonic current content and variable frequency AC power systems.^[2] In DO-160E, the entire section was re-ordered so that all the AC tests were in one subsection and all DC tests were in another subsection, making Section 16 easier to use and understand. DO-160E also introduced some new tests, such as a DC content test for AC powered equipment, and a new subsection covering "Load Equipment Influence on Aircraft Electrical Power Systems." In DO-160F, even more tests are required, for both AC and DC powered equipment. Additionally, a whole series of new tests and test levels to cover 270-volt DC power systems has been added, along with a greatly expanded list of tests to cover the EUT influence on the aircraft electrical power systems.

DC Input Tests
On DC inputs, there are tests that cover:

• Steady-state over- and under-voltage conditions
• Ripple voltage
• Momentary power interruption
• Momentary sags and surges
• Exposed voltage decay time (270 volt only)
• Inrush current

AC Input Tests
AC inputs are subjected to the following tests:

• Steady-state over- and under-voltage conditions
• Steady-state over- and under-frequency conditions
• Steady-state phase unbalance (three-phase power)
• Voltage and frequency modulation
• Voltage and frequency transients
• Momentary power interruption
• Momentary sags and surges
• DC offset and voltage distortion
• Harmonic current emissions
• Phase unbalance (three-phase inputs)
• DC current content
• Inrush current
• Current modulation
• Power factor

Equipment Categories
There are three equipment categories (A, B, D, or Z) that indicate the type of power used by the equipment and the type of AC and/or DC power source with which the equipment is compatible. For AC powered equipment, an additional designator, noted in parentheses following the category designator, is a two-character code indicating that the equipment has been tested for use with constant frequency (CF), narrow variable frequency (NF), or wide variable frequency (WF).

Up to four additional category designators are also used to indicate testing for:

• AC current harmonics (H)
• AC current modulation (L)
• AC power factor (P)
• DC current ripple (R)
• AC or DC inrush (I)

What's New for DO-160F?

• New category (D), tests, and test levels covering 270-Volt DC powered EUTs.
• Loss-of-Phase test for three-phase AC powered EUTs.
• Many additional tests in the "Load Equipment Influence on Aircraft Electrical Power Systems" section.
• Specific tolerances for all test parameters
• Specific definition of "Manual Reset"

SECTION 17: VOLTAGE SPIKE
This test determines whether the EUT can operate as required during and/or after voltage spikes are applied to the AC and/or DC power input(s). Any method of generating the spike may be used, provided that the pulse produced has a duration of at least 10 microseconds, a rise-time of less than two microseconds, and a source impedance of 50 ohms. A minimum of 50 voltage spikes is applied within one minute. This test is very similar to MIL-STD-461F test method CS106.^[3]

Equipment Categories
There are two equipment categories. The Category B test level is twice the AC (rms) and/or DC line voltage (or 200 volts, whichever is less). The Category A test level is 600 volts.

What's New for DO-160F?

• Requirement for testing all inputs simultaneously if they are all connected to the same power bus.
• Three-phase power test setup.
• Clarification of source impedance tolerance.

SECTION 18: AUDIO FREQUENCY CONDUCTED SUSCEPTIBILITY--POWER INPUTS
This test is performed to determine that the EUT will operate as specified when audio frequency interference is applied to the AC and/or DC power input. The test setup and procedure are nearly identical to MIL-STD 461F test method CS101, with the only difference being the actual test level and frequency range. The audio frequency interference is transformer-coupled onto each power input lead, and the peak-to-peak voltage level of the interference signal is measured across the power input and return leads. Test levels are up to 8 percent of the nominal AC input voltage, and the frequency range is as broad as 10 Hz to 150 kHz.

The EUT must be tested while operating at both minimum and maximum current draw (if applicable) and at the AC power frequency extremes if designated for use with variable frequency systems. The frequency scan rate is 30 steps per decade, with a one-minute dwell time at each frequency.

Equipment Categories
There are three DC power equipment categories (R, B, and Z) that indicate the type of power used by the equipment and the type of DC power source with which the equipment is compatible. The two AC power equipment categories are specified (R and K). Category R is used with an additional designation (a two-character code), placed in parentheses following the category designator, indicates that the equipment has been tested for use with constant frequency (CF), narrow variable frequency (NF), or wide variable frequency (WF). Category K designates that the EUT has been tested for use with any type of AC power input and has been tested to a higher level of voltage distortion than category R.

What's New for DO-160F?

• Three-phase power test setup.
• 270-VDC test category/level has been added (Figure 1).
• Common-mode test (at 2x the differential-mode level) for 270-VDC Category Z
• Requirement for testing all inputs simultaneously if they are all connected to the same power bus

Figure 1. Category Z, 270-Volt DC AF conducted susceptibility test level.

SECTION 19: INDUCED SIGNAL SUSCEPTIBILITY
The tests in this section are performed to determine that the EUT can operate as required when the equipment and interconnecting cables are subjected to audio frequency electric fields, magnetic fields, and transient voltage spikes. The test levels for the interconnecting cable tests are determined by the length of wire that is exposed to the radiating wire. For the inductive switching transients (induced spikes) test, the exposed length is either 1.2 or 3.0 meters, with the amplitude of the spikes applied to the radiating wire being at least 600 volts peak-to-peak.

For the magnetic and electric fields induced into cables, the test level is defined as the product of the length of interconnecting cable that is exposed to the radiating wire and the rms voltage or current applied to the wire. This test level is designated "volts x meters" (V-m), or "amps x meters" (A-m). For example, Category Z requires an electric field test level of 1800 V-m, which is typically obtained by exposing three meters of cable to a radiating wire with 600 volts rms applied to it. If, because of space restrictions, less than three meters of cable is exposed to the radiating wire, the voltage applied to the wire must be increased so that the test level of 1800 V-m is achieved. An exception to this requirement arises when the actual length of the cable in the final installation is known to be less than 3 meters. In such a case, the test level may be reduced in proportion to the ratio of the reduced coupling length.

The frequency ranges for the swept frequency tests are determined by the equipment category specified. The frequency scan rate is 30 steps per decade, with a 10-second dwell time at each frequency.

Equipment Categories
The equipment categories are indicated by two characters. The first character (A, B, C, or Z) indicates the tests performed and the severity level of the tests. The second character (C, N, or W) indicates the AC power system operating frequency (constant, narrow variable, or wide variable) with which the EUT is compatible.

What's New for DO-160F?

• No significant changes.

SECTION 20: RADIO FREQUENCY SUSCEPTIBILITY (RADIATED AND CONDUCTED)
These tests are performed to determine that equipment will operate as specified when the EUT and its interconnecting cables are exposed to radio frequency interference. Continuous wave (CW), square wave AM (SW), and pulse modulated (PM) RF signals are required. A Line Impedance Stabilization Network (LISN) must be inserted in series with each power lead and ungrounded power return lead, with a 10-�F capacitor connected between the power input of the LISN and the ground plane. Unless otherwise specified, interconnecting cables shall be at least 3.3 meters in length, and power leads should be no more than one meter in length for these tests.

Conducted Susceptibility
The RF conducted susceptibility test procedure is similar to MIL-STD-461F test method CS114. RF interference is coupled into the EUT interconnecting cables and power leads using an injection probe that is calibrated (in a 50-ohm fixture) to the required test level prior to performing the test. The amount of RF power applied to the injection probe that is required to achieve the specified RF current in the fixture is recorded for each test frequency. This calibration table, showing RF power required at a given frequency, is then used during the actual test.

During testing, the RF current that is induced into the cable or lead under test is monitored with a calibrated RF current probe, and the RF power applied to the injection probe is increased until the appropriate current level (as defined by the applicable equipment category used) is reached. The amount of RF applied to the injection probe is limited to no more than 6 dB above the power level recorded during calibration in the 50-ohm calibration fixture. The test frequency range is 10 kHz to 400 MHz, and two scans are typically required for each test?once with a CW signal, and then again with a SW modulated signal.

Radiated Susceptibility
The RF radiated susceptibility test procedure is similar to MIL-STD-461E test method RS103. The EUT and its interconnecting cables and power leads are exposed to RF radiated fields in the frequency range of 100 MHz to 18 GHz.

There are two RF radiated susceptibility test methods allowed in Section 20. The first uses a standard semi-anechoic chamber as in MIL-STD-461F test method RS103. The chamber must be lined with RF absorber, and the minimum performance of the absorber is specified. The minimum antenna distance is one meter, and multiple antenna positions are required when the beamwidth of the antenna does not totally cover the system. If the EUT has apertures, connectors, seams, or other points of penetration of the EUT enclosure, all of these must be exposed directly to the test antenna, necessitating multiple EUT positions during testing.

Calibration of the RF field prior to placement of the EUT is required. The RF power applied to the antenna input that is required to achieve the specified test level is recorded for each antenna used. During EUT testing, this calibrated power level for each test frequency is applied to the antenna. The second method uses a mode-tuned reverberation chamber, which must undergo a field uniformity validation and maximum chamber loading verification prior to the first use of the chamber, or after any modifications. Field uniformity and maximum electric field strength measurements are performed with a three-axis E-Field probe at up to nine different positions within the chamber. Also, a passive, linear antenna is moved to different positions within the chamber to calibrate the antenna for use prior to each test. This calibration allows the antenna to be used to measure chamber Q, time constant, and chamber loading factor, during EUT testing. As with the anechoic chamber method, the calibrated power level for each test frequency is applied to the antenna during EUT testing.

Equipment Categories
Equipment category designation for Section 20 is denoted by two letters. Conducted susceptibility test levels are designated with the first category character and radiated susceptibility test levels with the second category character. There are seven equipment categories for conducted susceptibility, and 10 equipment categories for radiated susceptibility. These categories indicate the severity level of the tests performed, and/or the type of modulation used. Category S is the least severe at one V/m, and Category L is the most severe, with test levels as high as 7200 V/m.

Examples of some of the conducted and radiated equipment categories are shown in Figure 2 and Figure 3.

 Figure 2. Category B, D, F, G, L radiated susceptibility test levels (CW & SW).

 

Figure 3. Category B, D, F, G, L radiated susceptibility test levels (pulse).

What's New for DO-160F?

• Reduced number of equipment categories.
• There is now only one test method for conducted susceptibility.
• Clarification has been added regarding the requirement to expose all apertures and openings of the EUT in anechoic chamber method.

SECTION 21: EMISSION OF RADIO FREQUENCY
The tests in this section are performed to determine that the EUT does not emit radio frequency interference in excess of the specified limits. Conducted RF emissions appearing on interconnecting cables and power leads are measured. Radiated RF emissions from the EUT, interconnecting cables, and power leads are measured as well.

Measurements must be made with an instrument using a peak detector, and with IF bandwidths, frequency step size, and dwell time as specified in Section 21, Table 1, for the frequency range being scanned.

A LISN must be inserted in series with each power lead and ungrounded power return lead, with a 10-�F capacitor connected between the power input of the LISN and the ground plane. Unless otherwise specified, interconnecting cables shall be at least 3.3 meters in length, and power leads should be no more than one meter in length for these tests. Ambient emission levels must be at least 6 dB below the applicable limit and must be measured and recorded if any signals are found to be within 3 dB of the applicable limit.

Conducted Emissions
Conducted RF currents on interconnecting cables and power leads are measured with a clamp-on current probe. The probe is positioned five centimeters from the EUT and measurements are made over the frequency range of 150 kHz to 152 MHz.

Radiated Emissions
Radiated RF fields are measured with a linearly polarized antenna over the frequency range of 100 MHz to 6 GHz. As with RF radiated susceptibility testing in Section 20, there are two RF radiated emissions test methods allowed in Section 21: the anechoic chamber method, and the reverberation chamber method.

The anechoic chamber method requires a chamber lined with RF absorber, and the minimum performance of the absorber is specified. The measurement antenna distance is one meter, and multiple antenna positions are required when the beamwidth of the antenna does not totally cover the system. If the EUT has apertures, connectors, seams, or other points of penetration into the EUT enclosure, all of these must be directly exposed to the test antenna, requiring multiple EUT positions during testing.

The second method uses a Reverberation Chamber, which requires a field uniformity validation as described in Section 20. EUT loading is measured after the EUT is installed in the chamber, and the data are used as a correction factor for the radiated emissions measurement. A minimum of 200 sweeps of the analyzer or measurement receiver is required over one rotation of the tuner for each measured frequency range.

Equipment Categories
There are four equipment categories (B, L, M, H, and P) that indicate the location of the equipment and the separation between the equipment and aircraft antennas. In general, the closer the equipment is to an aircraft antenna, and the more it approaches a "direct view" of an aircraft antenna, the tighter the emissions limits.

What's New for DO-160F?

• The conducted emissions frequency range has been broadened to 150 kHz - 152 MHz, and the Radiated Emissions test frequency range has been narrowed to 100 MHz - 6 GHz.
• A new procedure for radiated emissions measurements in a reverberation chamber has been added.
• In the anechoic chamber method, clarification has been added regarding the requirement to expose all apertures and openings of the EUT.
• A new limit category has been added--Category P--to provide added protection for certain receivers by use of even deeper "notches" than previously used (Figure 4 and Figure 5).
• Category P includes special notches in the radiated emissions limit that were added at the last minute at the insistence of RTCA Special Committee 159 to protect GPS receivers, in particular.

Figure 4. Category P conducted RF emissions limit?power leads.

Figure 5. Category P radiated RF emissions limit.

SECTION 22: LIGHTNING INDUCED TRANSIENT SUSCEPTIBILITY
These tests determine whether the EUT can operate as specified during and/or after various lightning induced transient waveforms are injected into connector pins, interconnecting cables, and power leads using pin injection, and/or cable bundle tests. The pin injection method is normally used to show damage tolerance, while the cable bundle tests are normally used to show upset tolerance. Change 3 to DO-160D, issued December 5, 2002, amounted to a considerable revision of Section 22, primarily adding procedures, waveforms, and test levels for multiple burst and multiple stroke cable bundle test methods. New waveform set designators (G through K) were also added to cover the multiple burst and multiple stroke tests.

Pin Injection
During pin injection testing, the EUT is normally powered so that the circuits being tested are biased as they would be in normal operation. The test level is defined as an open circuit voltage (Voc) with a specified source impedance from the generator. For example, waveform 3, test level 2 specifies Voc as 250 volts, with a short circuit current (Isc) of 10 amps. The ratio of Voc to Isc yields a generator source impedance requirement of 25 ohms. The generator is adjusted to produce waveform 3 with these specified characteristics, and the transient waveform is then applied directly to the interface pins. After the pins have been tested, the EUT is evaluated to determine if its performance has been degraded.

Cable Bundle Tests
Cable bundle tests are performed using either cable induction or ground injection to couple the transient waveforms into the interconnecting cable bundles and power leads.

The cable induction test method uses an injection probe to induce the transient waveforms into interconnecting cables and power leads. The ground injection method is very similar to the cable induction method, except that the transient waveform is applied between the EUT case and the ground plane. The EUT is isolated from the ground plane by lifting all local grounds and returns and by insulating the case from the ground plane, a step that forces the injected transient into the cable shields and any other return paths back to the ground plane.

A Line Impedance Stabilization Network (LISN) must be inserted in series with each power lead and ungrounded power return lead, with a 10-?F capacitor connected between the power input of the LISN and the ground plane for AC powered equipment, or with a 33,000-�F capacitor connected across the power inputs of the LISNs for DC powered equipment. Unless otherwise specified, interconnecting cables shall be at least 3.3 meters in length, and power leads will be no more than one meter in length for these tests.

For each waveform, either a voltage or current test level is given, along with a current or voltage limit. For example, waveform 2, test level 3, specifies a voltage test level (VT) of 300 volts and a current limit (IL) of 600 amps. These requirements mean that during the test, the generator level is increased until the peak voltage measured on a single turn monitor loop placed through the injection probe reaches 300 volts or until the monitored induced current in the cable or lead reaches the 600 amp limit.

Cable bundle tests may be performed using the single stroke method alone, or using a combination of the single stroke, multiple stroke, and multiple burst methods.

The single stroke test method is designed to represent the internal aircraft wiring response to the most severe external aircraft lightning strike. A single occurrence (stroke) of the specified test waveform is applied to the cable bundle or wire under test, and is repeated for a total of ten applications in each polarity.

The multiple stroke test method is designed to represent the induced effects to internal aircraft wiring in response to an external aircraft lightning strike that is composed of a first return stroke immediately followed by multiple return strokes (Figure 5).

The multiple burst test method is designed to represent the induced effects to internal aircraft wiring in response to an external aircraft lightning strike of a multiple burst nature (Figure 6). The specified test waveform is applied to the cable bundle or wire under test, and repeated for at least five minutes in each polarity.

Equipment Categories
Category designations consist of five characters that describe the pin and cable test waveform sets and test levels.

The three-pin Injection test waveforms are grouped in two waveform sets (A & B). The five cable bundle test waveforms are grouped in four Single Stroke Waveform Sets (C through F), and four combined Single Stroke, Multiple Stroke, and Multiple Burst Waveform Sets (G through K).

What's New for DO-160F?

• No significant changes to the test levels or methods.
• Clarification of waveform parameters added.
• Section was reorganized for readability by moving notes under figures to the proper paragraphs within the procedure.
• Guidance added for determination of test level of "noisy" waveforms.

SECTION 23: LIGHTNING DIRECT EFFECTS
The tests in this section are performed to determine the ability of externally mounted electrical and electronic equipment to withstand the direct effects of a severe lightning strike. The equipment will not normally be powered during the test, and these tests usually cause damage (sometimes spectacular damage) to the EUT. High voltage and/or high current tests at levels of thousands of kilovolts and/or hundreds of kilo-amps are required.

Equipment Categories
Category designations consist of four characters that describe the nature and severity of the test waveforms applied. The first two characters designate the high voltage strike attachment test category, and the last two characters designate the high current physical damage test category. The designated test category for the EUT should correspond to the lightning strike zone in which the EUT will be installed on the aircraft.

What's New for DO-160F?

• Clarification of test waveforms and methods has been added throughout the section, greatly improving the usability.
• Tables added and figures improved (and added) to make test procedures more understandable.
• Category designations have been added to separate voltage and current tests.
• Category designations have been clarified, and Category F has been deleted.

SECTION 25: ELECTROSTATIC DISCHARGE (ESD)
This test determines whether the EUT can operate as specified during and after being subjected to an electrostatic air discharge event. The test procedure and test generator used are similar to those used in most other international ESD standards, except that the EUT is bonded to the ground plane and only air discharge is specified. Test points are chosen based on their accessibility to personnel, with 10 positive and 10 negative polarity discharges at 15 kV applied to each one.

Equipment Categories
There is only one category (A), with a test level of 15 kV.

What's New for DO-160F?

• No significant changes, except correcting typographical errors in the figures.

The latest from SC-135:
From the most recent (March, 2008) meeting of SC-135, here is a sampling of some possible changes to look for in the future:

• A "User's Guide" appendix (informative only) will be added to many of the sections of DO-160.
• Section 16 will have even more tests and power types.
• Section 20 is to have "mode-stirring" re-introduced as an option for the reverberation chamber test method.
• Section 21 will be revised to include special limits and procedures to address protection of onboard GPS receivers used for navigation.
• Section 25 will be revised to add more test levels steps, contract discharge, and indirect discharge testing.

These revisions, and more, are proposed for inclusion in the new DO-160G, which is slated for publication in December 2010.

Summary
RTCA/DO-160, and its European twin, EUROCAE/ED-14, are truly the world standards for electromagnetic compatibility requirements for aircraft electronic equipment. The test levels, requirements, and procedures are intended to reflect the "state-of-the-art" in aviation technology and EMC testing methodology. Since both aviation technology and EMC testing methodology are evolving at a rapid rate, work is continuing on the next revision RTCA/DO-160.

REFERENCES

1. RTCA/DO-160E, "Environmental Conditions and Test Procedures for Airborne Equipment," RTCA, Inc., December 9, 2004.
2. RTCA/DO-160D, "Environmental Conditions and Test Procedures for Airborne Equipment," RTCA, Inc., July 29, 1997.
3. MIL-STD-461F, "Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment," Dept. of Defense Interface Standard, 10 December 2007.

Erik Borgstrom has worked in the EMC testing field for more than 21 years. He currently holds the position of EMC Operations Manager for Environ Laboratories LLC and specializes in the EMC testing requirements for the Defense and Aerospace industries. Mr. Borgstrom is an active member of the IEEE, and he serves as the IEEE EMC Society's liaison to RTCA as a member of the Standards Advisory and Communication Committee. Mr. Borgstrom is also active on SAE Committees AE-2 and AE-4 (HIRF), and is Environ's representative to RTCA, where he is an active member of RTCA Special Committee 135, serving as Change Coordinator for Section 25 (ESD) of DO-160.

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