For example: Agilent E4440A or Anritsu 68369
ETS-Lindgren
ETS-Lindgren 3816-2
9 kHz to 30 MHz 2-Line Sgl Ph 16 amp 50
Category: Line Impedance Stabilization Network
ETS-Lindgren 4825/2NM
9KHZ-30MHZ, ANSI/C63.4 CISPR 16 LISN
Category: Line Impedance Stabilization Network