For example: Agilent E4440A or Anritsu 68369
Keithley Instruments Signal Gen/Synthesizers/Sweepers
Keithley Instruments 2900-ALG
Flexible Analog Modulation signal gen.

Manufacturer: Keithley Instruments
Keithley Instruments 2900-DIG
Flexible Digital Modulation Signal Generation SW

Manufacturer: Keithley Instruments
Keithley Instruments 2920-FP-BT-004
10MHz - 4GHz RF Vector Signal Generator, Front RF Input Connection, Bench Top

Manufacturer: Keithley Instruments
Keithley Instruments 2920-FP-RK-004
10MHz - 4GHz RF Vector Signal Generator, Front RF Input Connection, Rack Mount

Manufacturer: Keithley Instruments
Keithley Instruments 2920-FP-RK-006
10MHz - 6GHz RF Vector Signal Generator, Front RF Input Connection, Rack Mount

Manufacturer: Keithley Instruments
Keithley Instruments 2920-RP-BT-004
10MHz - 4GHz RF Vector Signal Generator, Rear RF Input Connection, Bench Top

Manufacturer: Keithley Instruments
Keithley Instruments 2920-RP-BT-006
10MHz - 6GHz RF Vector Signal Generator, Rear RF Input Connection, Bench Top

Manufacturer: Keithley Instruments
Keithley Instruments 2920-RP-RK-004
10MHz - 4GHz RF Vector Signal Generator, Rear RF Input Connection, Rack Mount

Manufacturer: Keithley Instruments
Keithley Instruments 2920-RP-RK-004-LAR-LPN
10MHz - 4GHz RF Vector Signal Generator, Rear RF Input Connection, Rack Mount

Manufacturer: Keithley Instruments