Spread spectrum minimizes the EMI impact of switching power supplies and helps meet regulatory mandates. Noise is a concern and consideration for many circuit designs, and there are many types of noise. There is external noise, such as from nearby motors or RF interference sources, and internal noise, which is generated by various sources of […]
EMI/RFI
What are some common EMI/EMC tests?
An EMC test is known as Electromagnetic compatibility, a certification for electronic devices to maintain their limitation of electromagnetic waves. As discussed in the previous article, there are two types of EMC tests: emission (EMI) and immunity (EMS). EMI (Electromagnetic Interference) tests measure the magnetic waves emitted by the device, and EMS (Electromagnetic Susceptibility) tests […]
The basics: what is EMC?
EMC stands for Electromagnetic compatibility, which means that a device is compatible with (i.e., no interference is caused by) its electromagnetic (EM) environment. It does not emit levels of EM energy that generate electromagnetic interference (EMI) in other devices in the vicinity. Electromagnetic interference (EMI) is the interference caused by one electrical or electronic device […]
A comparison of EMI test setups and specifications for automotive, industrial and defense applications, part 2: Radiated emissions
By Timothy Hegarty, Applications Engineer, Texas Instruments This article compares electromagnetic compatibility (EMC) requirements in automotive, industrial and defense product family standards, specifically various test parameters, test equipment, test setups and test methods for radiated emissions (REs). Much like the treatment of conducted emissions [1] in part 1 of this two-part article series, the comparison […]
Keeping the noise down
By Patrik Kalbermatten, KEMET Compact nanocrystalline single-phase filters that suppress electromagnetic interference from the power provide engineers with greater design flexibility. In our increasingly connected world, we are ever more dependent on electronic equipment and devices and the semiconductors contained within. It is perhaps no surprise, then, to find that demand for components that […]
A comparison of EMI test setups and specifications for automotive, industrial and defense applications, part 1: conducted emissions
by Timothy Hegarty, Applications Engineer, Texas Instruments This article compares electromagnetic interference (EMI) requirements in automotive, industrial, and defense product family standards, specifically various test parameters, test equipment, test setups, and test methods [1-4] for conducted emissions (CEs). The comparison includes widely used dedicated standards in each industry: Comité International Spécial des Perturbations Radioélectriques (CISPR) […]
RF/Microwave bandpass filter implementations, Part 2: Cavity and comb filters
The well-known and extensively analyzed lumped-element bandpass filter is generally not suitable for the RF/microwave region, but there are many distributed-element, energy-based alternatives. Part 1 of this article established the context for these RF/microwave filters, which operate in the spectrum from several hundred MHz and higher, and increasingly cannot use discrete lumped-circuit elements (RLCs). Instead, […]
RF/Microwave bandpass filter implementations, Part 1: Distributed filters
The well-known and extensively analyzed lumped-element bandpass filter is generally not suitable for the RF/microwave region, but there are many distributed-element, energy-based alternatives. Just say the word “filters,” and for many engineers, the mention of this topic stirs a mix of feelings ranging from fear to relief. Why fear? Because filters as a topic in […]
Rudiments of radiated EMI/EMC
Radiated emissions standards are generally more focused on higher-frequency noise sources. At about 30MHz, there is a transition between concern with conducted and radiated emissions. Above that frequency, conducted emissions are not usually a major problem. And below 30MHz, the various interconnects and conductors in most electronic systems are not effective antennas for emitting radiated […]
Conducted and coupled EMI/EMC concepts
In addition to the International Telecommunications Union (discussed in part 1 of this FAQ series), there are several organizations that define and regulate acceptable levels of conducted and radiated emissions from electronic devices. These various agencies have developed numerous standards generally based on the operational environment of the specific device. Effectively managing EMI is a […]
