Spectrum analyzer is an instrument to study the structure of electrical signals. Signal parameters such as signal distortion, modulation, spectral purity, frequency stability and cross modulation distortion are measured. Also available to measure the amplifier and filter circuit system, some of the parameters, is a multi-purpose electronic measuring instrument.
It can also be called frequency domain oscilloscope, tracking oscilloscope, analytical oscilloscope, harmonic analyzer, frequency characteristic analyzer or Fu Liye analyzer, etc.. The modern spectrum analyzer can display the analysis results in analog or digital way, and it can analyze the radio signal of the whole radio frequency range of 1 Hz to sub millimeter wave band.