Spectrum Analyzers

Spectrum analyzers are one of the most common instruments used in a measurement laboratory (often integrated into the oscilloscope) and it is an imperative skill of a scientist to be able to handle a spectrum analyzer and to interpret its output. A spectrum analyzer is the most basic application of transform theory, and this chapter relies heavily on the previous chapter. Spectrum analyzers can be analog (non-sampling) or digital (sampling). Both kinds of analyzers are treated in this chapter, but the focus is on sampling systems based on the fast Fourier transform. Fundamental spectrum concepts like spectral leakage and windows, resolution bandwidth, and heterodyne analyzers are highlighted and illustrated by examples.