ABSTRACT
Spectrum analysis is normally done in order to verify the harmonic content of oscillators, transmitters, frequency multipliers, etc., or the spurious components of amplifiers and mixer. Other specialized applications are possible, such as the monitoring of radio-frequency interference, electromagnetic interference, and electromagnetic compatibility. These applications, as a rule, require an antenna connection and a low-noise, external amplifier. This chapter provides a list of the typical characteristics of a spectrum analyzer. When more accurate measurement of power sources, with slow time variations, is needed, the suggestion is to use a bolometer instead of a spectrum analyzer. Handheld spectrum analyzers are very popular nowadays, being low cost, with a high level of performance for their deep usage of the newest digital processing techniques. Fundamental research like radio astronomy has found a great benefit from the technological developments opening new possibilities in advanced spectrum analysis applications. Autocorrelators, with a typical frequency resolution of 5/25 kHz, have been extensively used in radio astronomy.
