Whitepaper
Reducing Scepticism in Emissions Measurements
This article from Com-Power argues that deeper familiarity with RF emissions test system design is essential for building confidence in lab pass/fail decisions. It walks through the core field strength equation (E = V + AF + C – G) and explains why none of the system components have flat frequency responses, requiring correction data to be loaded at calibration and verified with comb generators before each test run. The article then applies the Friis noise equation to demonstrate why a pre-amplifier must be placed before the long interconnecting cable rather than after it — a counterintuitive but mathematically clear conclusion that yields a 10 dB improvement in signal-to-noise ratio. Practical solutions such as integrated active horn antennas are presented. The conclusion emphasizes that an engineer who understands the system's design limitations will inspire far greater confidence in test results than one who operates the equipment blindly.