This 2 GH - 22 GHz high gain, low noise preamplifier increases the sensitivity of any microwave spectrum analyzer. By improving sensitivity, you can detect and analyze very low level signals in dramatically reduced measurement time. Ordinarily, detecting low level signals requires the use of narrow bandwidths. As bandwidths are narrowed, however, sweeping becomes longer and measurement speed is reduced. The improved sensitivity added by the 8449A lets you widen bandwidths and measure low level signals using much shorter sweeptimes.
Keysight 8449A Specs
||2 GHz - 22 GHz