Comparing Spectrum Analyzers – GPSA v RTSA

The spectrum analyzer and the oscilloscope are two of the most used electronic devices for the measurement of electric signals. Whilst oscilloscopes present the final information in the time domain on a screen, spectrum analyzers display the intensity (vertical axis) of electric signal information in the frequency domain (horizontal axis). Currently, it is possible to find oscilloscopes able to handle high-frequency signals in the gigahertz frequency band. However, oscilloscopes have an important limitation: as the frequency increases, the noise floor displayed in the time domain also increases, making it difficult to distinguish low-intensity signals, such as harmonics and spurious signals, from the background noise. Thus, spectrum analyzers represent the best tool when working with high-frequency signals. The most advanced spectrum analyzer can work from some kilohertz to various tens of gigahertz. There are even spectrum analyzers applied to optics for measuring fiber-optic signals.