For example: Agilent E4440A or Anritsu 68369
Vaunix Attenuator
Vaunix LDA-302P-1N
10 - 3000 MHz Digital Attenuator, 2 Watts, 1.0 dB, N Connectors
Manufacturer: Vaunix
Vaunix LDA-302P-2N
10 - 3000 MHz Digital Attenuator, 2 Watts, 2.0 dB, N Connectors
Manufacturer: Vaunix