Spectrum analyzers are used to display the amplitude distribution over a certain frequency range. 
This spectrum analyzer thus makes visible the individual spectral components with the corresponding amplitudes, which is making this device indispensable for the assessment and diagnosis of modern, high-frequency electronic systems. Due to the high frequency bandwidth and dynamic, modern spectrum analyzers are superior in many measurement areas contrary to the use of oscilloscopes and therefore preferable for the application. 
The high technical performance and many features makes this device ideal tools in industry, development, EMC diagnostic and quality assurance.