The 8970A Noise Figure Meter is a very sensitive, tunable, automatic receiver. Its capability is greatly enhanced by a microprocessor used for many control, timing, and calculation purposes. With an appropriate solid state noise source, such as the 346B Noise Source, it automatically measures the noise figure of the device under test (DUT) inserted between the output of the noise source and the input of the 8970A. The 8970A may be tuned to any frequency between 10 and 1500 MHz and digitally swept over all or part of this range. To measure DUT’s with output frequencies greater than 1500 M Hz, an external mixer and local oscillator (LO) are required to down convert the frequency into the 10 to 1500 M Hz range. The 8970A can also automatically remove the noise contribution of the second stage (the measurement system) from the measurement. It can measure and display both gain and noise figure of the DUT.