Many people use “spectrum analyzer” to refer to signal analyzers. While the terms signal analyzer and spectrum analyzer are not interchangeable, they often refer to the same measurements and concepts. Along with these new high-functioning signal analyzers, more compact options have come about, such as the Keysight FieldFox and modular spectrum analyzers. Today’s signal analyzers combine functionality of the earlier evolutions of spectrum analyzers, such as analog, vector, and FFT (fast Fourier transform) measurements. Vector signal analyzers measure the magnitude and phase of an input signal at a single frequency. Spectrum analyzers measure the magnitude of an input versus signal frequency. With the need for phase measurements, signal analyzers took the place of their more basic counterparts. These swept-tuned, super heterodyne analyzers evolved over time with the communications industry. Spectrum analyzers originally measured only amplitude. Not to be confused with a power meter, a modern spectrum analyzer performs digital signal processing with added capabilities to dive deeper into signals.
To begin, a spectrum analyzer (at the most basic level) functions as a frequency-selective, peak-responding voltmeter calibrated to display the RMS (root-mean-square) value of a sine wave. In this blog, I’ll go over the basics of spectrum analyzers to lay a foundation of understanding. From simple amplitude and frequency measurements to complex, application-specific measurements, there’s a lot to cover and understand. The concept of spectrum analysis is a little daunting. Spectrum Analysis Basics, Part 1 – What is a spectrum analyzer?