Modern high-end oscilloscopes contain high-speed analog-to-digital converters (ADCs), which allow them to cover frequency ranges that historically could only be investigated using a spectrum analyzer. By also integrating a high-bandwidth analog front end, modern oscilloscope architectures enable direct sampling of high-frequency signals without analog downconversion, leading to unprecedented analysis bandwidth ranges.
Some oscilloscopes in the market today have a bandwidth of up to 16 GHz and are capable of directly acquiring a nominal 8-GHz RF signal with 16-GHz bandwidth. As of now, this can’t be done with a signal and spectrum analyzer.
Spectrum analyzers, on the other hand, can cover frequency ranges up to 85 GHz and beyond, enabling them to address most applications of wireless, cellular or satellite communications, radar equipment, and IoT devices. For such apps, qualities exclusive to spectrum analyzers come to the fore.