The signal that is being converted and displayed on the screen is always electric, however it is possible to analyze other types of signals like sound (vibration) and light waves. They require a special probe with a converter that is able to recognize the desired signal and transform it into a respective electrical signal prior to sending it to the analyzer. If the signal is received by such device, its amplitude is measured against its frequency. A spectrum analyzer is capable of measuring and displaying a variety of parameters, however there are three basic measurements that are made more commonly that the others. Modulation is measured to establish if the information embedded in the signal is being transfered correctly. Noise is an important parameter because it determines the actual “amount” of your signal that is received by other stations, and how much information is lost. Distortion determines if there are any interferences with other signals. If two signals are cross-interfering both of them will be distorted and therefore will be useless.

There are two types of signal analyzers. The first one is called FFT analyzer. It receives a time-domain based signal over a period of time, digitizes it and performs necessary calculations and mathematical operations to transform it into a frequency-domain signal. The second type is called swept-tuned. These devices scan a great range of frequency and display all necessary parameters.