Making RF Power And Frequency Measurements With Spectrum And Signal Analyzers

By National Instruments

Overview

This application note explains how fundamental RF power and frequency measurements are made with both traditional spectrum analyzers and with more modern FFT-based analyzers. The document also covers instrument controls and how they affect your measurement results.

Introduction

Frequency-domain measurement of RF power is one of the most basic measurements performed by traditional spectrum analyzers and modern vector signal analyzers. For example, interoperability of communication systems requires these systems to comply with standards-based limits on power transmitted in the assigned bands as well as undesired or spurious emissions in neighboring bands -- one person's music is somebody else's noise. Unless appropriate measurement techniques are applied, results can incur significant errors. The goal of this application note is to cover some instrument and measurement basics to avoid such errors.