What are the main types of spectrum analyzers?

There are two main types of spectrum analyzers: sweep tuning analyzers and real-time analyzers. Modern spectrum analyzers use digital signal processing to provide more measurement capabilities, making it easier for you to interpret your measurements. Whether it's a swept-tuning analyzer or a real-time spectrum analyzer, they both display the change in amplitude with frequency. But how exactly does each analyzer process and display this information? A real-time spectrum analyzer displays the energy of all frequency components simultaneously. A swept-tuned spectrum analyzer displays measurements sequentially, in other words, it does not measure in "real time". This is because a swept-tuned analyzer uses a narrow filter that is tuned over a range of frequencies to produce the spectrum display.