For example: Agilent E4440A or Anritsu 68369
Rigol Function/Arbitrary Waveform Generators
Rigol DG1022
Function / Arbitrary Waveform Generator - DG1000 Series 2 CH, 20 MHz
Manufacturer: Rigol
Rigol DG2021A
25 MHz Function/arbitrary waveform generator (LAN/GPIB) -Discontinued
Manufacturer: Rigol
Rigol DG3101A
100 Mhz DDS Function/Arbitrary Waveform Generator (USB/RS-232/LAN/GPIB)
Manufacturer: Rigol