Editing Spectrum analyzer (section)

== Radio-frequency uses ==

Spectrum analyzers are widely used to measure the [[frequency response]], [[Electronic noise|noise]] and [[distortion]] characteristics of all kinds of [[radio-frequency]] (RF) circuitry, by comparing the input and output spectra. For example, in RF mixers, spectrum analyzer is used to find the levels of third order inter-modulation products and conversion loss. In RF oscillators, spectrum analyzer is used to find the levels of different harmonics.

In [[telecommunications]], spectrum analyzers are used to determine occupied bandwidth and track interference sources. For example, cell planners use this equipment to determine interference sources in the [[GSM frequency bands]] and [[UMTS frequency bands]].

In [[electromagnetic compatibility|EMC testing]], a spectrum analyzer is used for basic precompliance testing; however, it can not be used for full testing and certification.  Instead, an EMI receiver is used.

A spectrum analyzer is used to determine whether a wireless transmitter is working according to defined standards for purity of emissions. Output signals at frequencies other than the intended communications frequency appear as vertical lines (pips) on the display. A spectrum analyzer is also used to determine, by direct observation, the bandwidth of a digital or analog signal.

A spectrum analyzer interface is a device that connects to a wireless receiver or a personal computer to allow visual detection and analysis of electromagnetic signals over a defined band of frequencies. This is called panoramic reception and it is used to determine the frequencies of sources of interference to wireless networking equipment, such as Wi-Fi and wireless routers.

Spectrum analyzers can also be used to assess RF shielding. RF shielding is of particular importance for the siting of a magnetic resonance imaging machine since stray RF fields would result in artifacts in an MR image.<ref>{{cite web |url=http://www.aapm.org/pubs/reports/RPT_100.pdf |title=Archived copy |access-date=2012-04-11 |url-status=live |archive-url=https://web.archive.org/web/20111120045254/https://aapm.org/pubs/reports/RPT_100.pdf |archive-date=2011-11-20 }}</ref>