A spectrum analyser is an instrument that shows signal amplitude or strength as it changes by signal frequency. The amplitude is displayed on the vertical axis while the frequency is displayed on the horizontal axis. It looks like an oscilloscope.
A typical application of a spectrum analyser is to determine whether a wireless transmitter is working according to specifications laid down for its use by the sanctioning authority. If the output signals differ from the recommended frequency they will appear as vertical lines on the display. Government regulators usually use a handheld spectrum analyser to quickly monitor a wireless transmitter. It can also be used to find out competing frequencies that are acting as interference to wireless networking equipment like Wi-Fi routers. The electromagnetic signals from the interfering transmitter can be found out by a technique called panoramic reception. Designing with Bluetooth or interference hunting is a task best suited for RF analysers. There are USB spectrum analysers and benchtop real time analysers in the market. Handheld analysers can detect in the frequency range of 10 kHz to 6.2GHz. Advanced analysers are used to detect android device microphone by frequency detection.
The costs of spectrum analysers has dropped low enough that affordability is no more an issue. In normal use these analysers check the measurement of bandwidth of modulated signals and also the efficiency of filters and networks. In that sense the use of the analyser is a powerful tool for other measurements like RF network analyser, frequency counter and power meters.
