As for the spectrum analyzer, may be we will know. Actually,it is an Electronic Instruments the same as Power Analyzer.It mainly used for studying the spectral structure of electrical signals. It can be used to measure the signal distortion, modulation, spectrum purity, frequency stability, and crosstalk, and can be used to measure certain circuit systems such as amplifiers and filters. The parameter is a multi-purpose electronic measuring instrument. It can also be referred to as a frequency domain oscilloscope, tracking oscilloscope, analytical oscilloscope.