For example: Agilent E4440A or Anritsu 68369
Distortion Analyzers
Keysight / Agilent 8903A
Audio Analyzer provides automatic measurements of distortion
Manufacturer: Keysight / Agilent
Summitek SI-1900A
Summitek SI-1900A Passive Intermodulation Distortion Analyzer, 1850-1990 MHz
Manufacturer: Summitek
Summitek SI-2000B
Summitek SI-2000B Passive Intermodulation Distortion Analyzer, 1920-2170 MHz
Manufacturer: Summitek
Summitek SI-900A
Summitek SI-900A Passive Intermodulation Distortion Analyzer, 890 to 960 MHz
Manufacturer: Summitek