The 6600 Series Programmable Sweep Generators are a family of GPIB-capable signal sources that generate sweep and CW frequencies from 10 MHz to 40 GHz. A representative list of available model numbers, with the frequencies they cover, is given below. This list will expand as additional frequency ranges are added to the 6600 Series family. The Model 6637, 6638, 6647, and 6648 Programmable Sweep Generators are micropror cessor-based, pushbutton-controlled, broadband (see above), programmable sweep or fixed-frequency sources. When configured with the GPIB interface option (Option 3), any sweeper model is capable of being fully programmed via the IEEE 488 Interface Bus (GPIB).