RF test instruments are highly complex products with a wide variety of specifications that characterize the performance of each instrument. This article is the third and final part of a series that details common RF instrument specifications. Understanding RF Instrument Specifications Part 1 examines generic RF specifications that apply to all RF instruments. Understanding RF Instrument Specifications Part 2 covers specifications that are significant to RF continuous wave and vector signal generators. This final article focuses on specifications that apply to RF signal analyzers. Because there are two major types of RF signal analyzers, vector signal analyzers and spectrum analyzers, we first explain the distinctions between both instruments. Then we provide an introduction to specifications that apply specifically to spectrum measurements that include dynamic range, averaging methods, and displayed average noise floor.