The 6638A Sweep Generator is a high performance, programmable sweep generator. All front panel controls are accessible via GP-IB (optional). The unit has excellent signal purity, frequency stability and power level accuracy to within 1 dB. Five sweep modes and three built-in markers are available. It can be phaselocked to an external counter for even greater frequency accuracy. Frequency Range: 2GHz to 20Ghz, Output level: > 3.1 mW (internally leveled).