Amplifier Research

EMC 101

This introductory application note explains the fundamentals of electromagnetic compatibility and electromagnetic interference for those new to the field. It defines core terminology including EMC, EMI, EUT, conducted emissions, radiated emissions, conducted immunity, and radiated immunity, with diagrams illustrating typical test setups for each. The document distinguishes between continuous and transient test phenomena: continuous testing verifies that a device operates correctly in the presence of sustained RF signals across a defined frequency range, while transient testing simulates real-world events such as electrostatic discharge, lightning-induced surge, and relay switching. Impedance is identified as the most fundamental concept underpinning EMC, influencing everything from cable shielding to antenna effectiveness. The note then walks through practical steps for a manufacturer bringing a product to market, covering when to seek external test lab services versus building in-house capability, the importance of pre-compliance testing, and how US (FCC Part 15) and European (EMC Directive 2014/30/EU) regulatory frameworks apply.

EMC Standards Overview

Amplifier Research

This application note provides a structured overview of the major international and regional organizations responsible for developing and maintaining electromagnetic compatibility standards. It explains the four test categories — Radiated Immunity, Radiated Emissions, Conducted Immunity, and Conducted Emissions — and then surveys the key standards bodies, including the IEC and its subcommittees CISPR and TC 77, along with ISO, ITU, CENELEC, ETSI, the US DoD (MIL-STD-461 and MIL-STD-464), the FCC, and ANSI. The document outlines how standards are categorized as basic, generic, or product-specific, and walks through the IEC publication lifecycle from preliminary stage through approval. It concludes with practical guidance on which version of a standard to use, noting that military testing requires adherence to the exact revision specified in a contract, while commercial testing generally demands compliance with the latest published version. Major product segments and their governing standards — automotive, aviation, military, medical, ISM, and multimedia — are also summarized.

EMCware: Comprehensive Software for EMC Testing

This application note describes AR RF/Microwave Instrumentation's emcware v4.0 software, a unified EMC test management platform covering all four test categories — Radiated Immunity, Conducted Immunity, Radiated Emissions, and Conducted Emissions — in a single package with over 500 pre-defined test setups. The Equipment List Manager allows users to store instrument information, calibration dates, and correction factors, and includes a library of over 300 pre-loaded equipment drivers. The software supports fully automated calibration and test procedures for immunity testing, with signal routing configuration presented as a visual block diagram and EUT monitoring available through National Instruments DAQ cards or other remote interfaces. A Report Event tool enables engineers to pause tests and investigate anomalies without losing data. For emissions testing, emcware supports pre-scan and final measurement workflows with built-in limit line management, ISM exception handling, and investigation tools. Reports can be exported to Word, Excel, or PDF formats. The note concludes by positioning emcware as a cost-effective alternative to competitors who sell each test category as a separate software package.

Field Analyzers in EMC Radiated Immunity Testing

Amplifier Research

This application note from AR RF/Microwave Instrumentation explains the limitations of conventional RF field probes in EMC radiated immunity testing and introduces Field Analyzers as a more capable alternative. Standard diode-based probes are designed to measure RMS continuous wave fields, but produce unreliable or erroneous results when measuring modulated fields because their analog response time and slow sample rates interact unpredictably with modulation envelopes. Thermocouple-based probes can average pulsed fields but require prior knowledge of the modulation to derive maximum RMS values and cannot display the modulation envelope visually, leaving no way to verify waveform integrity or detect distortion such as overshoot, droop, or ringing introduced by amplifiers driven into saturation. AR's FA7000 series Field Analyzers address these limitations by using an isotropic diode-based field sensor that samples the composite electric field at a significantly faster rate than conventional probes, transmitting data digitally over optical fiber to a processor unit. This architecture enables direct measurement of maximum, minimum, and average RMS values for both AM and pulsed fields, as well as pulse rise time, period, and duty cycle from a time-domain oscilloscope-style display accessible via an embedded webpage on any web-enabled device. The system supports frequency correction factor tables for up to 30 points, multiple trigger modes including free-run, level, and external, and full remote control via USB, GPIB, and Ethernet for integration into automated test software. The sensors are laser powered, eliminating battery management during continuous testing. Compatible modulations covered include those required by DO-160, IEC 61000-4-3, ISO 11452, and MIL-STD-461.

Specifying RF/Microwave Power Amplifiers for EMC Testing

Amplifier Research

This application note from AR RF/Microwave Instrumentation guides EMC test engineers through the process of selecting the right power amplifier for electromagnetic compatibility testing. It begins by surveying common EMC test standards across military, aviation, automotive, and commercial sectors, then defines key amplifier specifications such as frequency response, rated output power, P1dB compression, harmonic distortion, gain, flatness, efficiency, mismatch tolerance, and pulse capabilities. The document compares Class A and Class AB solid-state amplifiers, noting that Class A designs offer superior linearity, ruggedness, and mismatch tolerance while Class AB units are more compact and cost-effective. Traveling Wave Tube Amplifiers (TWTAs) are discussed as a legacy high-power option with drawbacks including high harmonics, lower reliability, and longer lead times, while solid-state pulse amplifiers are presented as a modern alternative. Dual-band amplifiers, complete test systems, multi-tone testing efficiency, GaN transistor technology, and regulatory compliance considerations round out the guide.