For example: Agilent E4440A or Anritsu 68369
Sources
Keysight / Agilent 08753-60003
RF Source Module Assembly 300 KHz - 3 GHz
Manufacturer: Keysight / Agilent
Keysight / Agilent 08753-60146
RF Source Module Assembly, 30 KHz - 6 GHz
Manufacturer: Keysight / Agilent
Keysight / Agilent 08753-60230
TBR Source Assembly - 6 GHz Option 611 6Ghz source assembly for 8753E
Manufacturer: Keysight / Agilent
Keysight / Agilent 08753-60231
RF Source Module Assembly, 300 KHz - 3 GHz (No OPT 006 or 011)
Manufacturer: Keysight / Agilent
Keysight / Agilent 08753-60232
RF Source Module Assembly, 300 KHz - 3 GHz (OPT 011)
Manufacturer: Keysight / Agilent
Keysight / Agilent 08753-69231
RF Source Module Assembly, 30 KHz - 3 GHz Factory refurbishment of -60231
Manufacturer: Keysight / Agilent