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CS105 EMC Conducted Susceptibility Cross Modulation 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.

Keystone takes pride in providing the peace of mind that all of your MIL-STD-461 testing needs will be met. Our MIL-STD-461 test engineers work with clients to quickly develop appropriate and concise test plans. Additionally, we are in constant communication throughout the entire test process. We tailor each test plan to individual customer needs minimizing unnecessary costs and over-testing. 

Request a quote to receive expert MIL-STD-461 testing services tailored to your specific needs. Ready to get started? We are. Contact us to see why so many companies work with us to achieve their EMC lab testing needs. 

Summary of MIL-STD-461 Test Method of Antenna Ports and Cross Modulation Information

This EMC receiver front-end CS conducted susceptibility and immunity test is applicable from 30 Hz to 20 GHz. However, it is only relevant for receivers that normally process amplitude-modulated radio frequency (RF) signals.

The electromagnetic compatibility equipment under testing (EUT) must not exhibit any undesired responses. This is due to cross modulation beyond specified tolerances when subjected to the limit requirements. The limit requirements are provided by this individual EMC MIL-STD-461 standard.

The conducted susceptibility EMC testing procedure is used to determine the presence of cross-modulation products. The presence of these products may be caused by undesired signals at the EUT antenna ports.

Lastly, the required EMC testing equipment, setup, 461-test procedures are determined in agreement to the EMC test lab. Data results are also determined in accordance with the guidance within this military test.

Scope of MIL-461 Standard Testing of CS105 Compliance Devices

This EMC unintentional radiator test is suited for devices from 30 Hz to 20 GHz. However, it is only applicable to receivers that normally process amplitude-modulated RF signals. This is as a response to antenna-connected receiving subsystems. This effect results from a strong out-of-band signal near the operating frequency of the receiver that modulates the gain in front-end of the receiver and adds amplitude varying information to the desired signal.

The requirement for EMC MIL-STD 461 compliance testing should be considered only for receivers, transceivers and other similar devices. These include devices which extract information from the amplitude modulation of a carrier.

There is a wide diversity of subsystem designs being developed. The applicability of this type of requirement and appropriate limits need to be determined for each EMC procurement. Requirements need to be specified. These requirements must be consistent with the signal processing characteristics of the subsystem and the particular EMC test procedure to be used to verify the requirement.

One approach for determining the EMC levels required for the out-of-band signal can be determined from an analysis of the electromagnetic environments. These environments are present and a characteristic of receiving antennas. However, levels calculated by this means will often place unreasonable design penalties on the receiver.

One complicating factor is that one of the out-of-band signals typically is modulated with a waveform normally used by a receiver. Another factor includes the out-of-band signal normally specified to be close to the receiver operating frequency. Some receivers constantly change frequency. An appropriate relationship must be established for only short periods for a fixed frequency out-of-band signal.

MIL-STD 461 Lab EMC Immunity Testing Procedures

There are a large variety of receiver designs being developed. For this reason, the requirements for the specific operational characteristics of a receiver must be established. This is performed before meaningful test procedures are carried out.

Cross modulation EMC testing is only applied to receiving subsystems such as receivers. It is also only applied to RF amplifiers, transceivers and transponders which extract information from the amplitude modulation of a carrier.

Several receiver characteristics must be known for proper EMC device testing. These characteristics are usually determined by the test. The maximum signal input that the receiver can tolerate without overload needs to be known. This will help ensure that the test levels are reasonable.

The basic concept with this MIL-461 test is to apply modulated signal out-of-band to the receiver. This MIL-STD 461 test also determines whether the modulation is transferred to an unmodulated signal at the receiver’s tuned frequency resulting in an undesired response.

Keystone Compliance Provides Expert EMC Compliance Services and Military Standard Testing

Keystone Compliance can accommodate fixed, mobile and portable devices of all sizes. In addition to EMC MIL-STD-461 testing, Keystone has a full scope of expertise including environmental and package testing such as temperature, accelerated aging, and ingress protection. Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. 

If you are ready to start your CS105 MIL-STD-461 and EMC testing, please request a quote. Have a question about conducted susceptibility specifications or our electromagnetic compatibility testing lab? Contact us or call (724) 657-9940 and we will determine the best course of action.