For example: Agilent E4440A or Anritsu 68369
Xantrex AC Power Supplies
Programmable AC Power Sources, Frequency Converters
Xantrex CW1251M
CW1251M 1250 VA, ContinuousWave AC Power Source - Manual - CW Series
Manufacturer: Xantrex
Xantrex CW2501M
AC Power Source, 2.5 KVA, 1Ø, 135/270 VAC, 45 - 500 Hz (1 KHz optional)
Manufacturer: Xantrex
Xantrex CW2501P
CW2501P 2500 VA, ContinuousWave AC Power Source - Programmable - CW Series
Manufacturer: Xantrex