MIL-461 CE102 Conducted Emissions and EMC Testing
As a leader in EMC regulatory compliance testing, Keystone Compliance assists electronic equipment manufacturers with MIL-STD 461 EMC testing. Meeting the IEC, EN, and other MIL-STD-461 testing requirements can be challenging. Not only do we understand the challenges, but we help guide companies through the process.
Strategic partnerships allow us to meet customer needs beyond our scope of accreditation. Our accurate test reports are delivered quickly using our “four-eyes” approach. Meaning that multiple engineers and technicians review each report, ensuring that all the information required is present.
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Summary of EMC Conducted Emissions Unintentional Radiator Testing
MIL-STD 461 testing is applicable to product development devices from 10 kHz to 10 MHz. This is for all power leads, including returns, which obtain power from other sources not part of the Equipment Under Testing (EUT).
This MIL-461 standard electromagnetic compatibility (EMC) device testing procedure verifies that the electromagnetic emissions from the EUT do not exceed specified requirements.
Scope of EMC MIL-STD 461 Military Testing
The basic concept in the lower frequency portion of the conducted emissions MIL-STD 461 compliance requirements ensure that the EUT does not corrupt the power quality on the power buses present on the platform. There is no need for separate EMI requirements in output leads since power quality standards govern allowable distortion on output power. Also, since voltage distortion is the basis for establishing power quality requirements, the CE102 limit is in terms of voltage.
The basic limit curve for 28 V is placed roughly 20 dB below the power quality curve. One reason this is done is because a number of interference sources may be contributing to the net interference voltage present.
At higher frequencies, the electromagnetic compatibility EMC CE102 limit serves as a separate control from RE102. The CE102 limits are placed to ensure that there is no conflict with RE102. Emissions at the CE102 limit should not radiate above the RE102 limits.
The data concluding this CE electromagnetic compatibility military standard test is presented as follows:
- Amplitude versus frequency profiles are continuously and automatically plotted. Manually gathered data is not acceptable except for plot verification.
- Applicable limits are shown.
- A minimum frequency resolution of 1% or twice the measurement receiver is provided.
- Lastly, plots of both the measurement system check and measurement portions are provided in the MIL-STD 461 lab test report.
The requirements are applicable from 10 kHz to 10 MHz. These EMC requirements are for leads including returns, which obtain power from other sources not part of the Equipment Under Testing (EUT). There is no requirement on output leads from power sources.
Conducted Emissions MIL-STD-461 Standard EMC Testing Procedures
Emission levels are determined by measuring the current present on each power lead. Current is measured because of the low impedances present over most of the frequency range of the test. During the measurement system check, the signal generator is supplemented with a power amplifier. This is done to obtain the necessary 6 dB below the applicable limit.
An alternative test procedure for high current loads may be useful. For an AC bus, a distortion meter is used rather than a measurement receiver. If a distortion meter is not available, the peak AC voltage is measured in an open circuit as loaded by the EUT.
The electromagnetic compatibility (EMC) and conducted emission test procedures are run as follows:
- A measurement integrity check is performed.
- This is done by turning on the measurement equipment. Next, a signal is applied to the power output terminal.
- The measurement receiver is then scanned for each frequency in the same manner as a normal data scan.
- If readings are obtained which deviate by more than 3 dB, the source of the error is located and corrected prior to continuing the testing.
- The EUT testing is performed next.
- The EUT is turned on and sufficient time is allowed for stabilization.
- The appropriate lead is then selected for testing.
- Next, the measurement receiver is scanned. This is done over the applicable frequency range.
Expert Compliance Testing of Conducted Emissions and EMC Equipment
Keystone Compliance can accommodate fixed, mobile and portable devices of all sizes. In addition to EMC CE102 testing, Keystone has a full scope of expertise including environmental and package testing such as vibration, accelerated aging, and ingress protection. Our team strives to give our customers more time and energy on product development instead of testing.
For more information on general MIL-461 testing and test standards, please visit the links below: