Ordering Number	Model Name	RF Signal Generator Description
E4400A	HP ESG-1000A	250 kHz to 1 GHz Analog
E4420A	HP ESG-2000A	250 kHz to 2 GHz Analog
E4421A	HP ESG-3000A	250 kHz to 3 GHz Analog
E4422A	HP ESG-4000A	250 kHz to 4 GHz Analog
E4430A	HP ESG-D1000A	250 kHz to 1 GHz Digital and Analog
E4431A	HP ESG-D2000A	250 kHz to 2 GHz Digital and Analog
E4432A	HP ESG-D3000A	250 kHz to 3 GHz Digital and Analog
E4433A	HP ESG-D4000A	250 kHz to 4 GHz Digital and Analog