N8973A: 10 MHz to 3 GHz N8974A: 10 MHz to 6.7 GHz N8975A: 10 MHz to 26.5 GHz SNS Series noise source compatibility Color graphical display with markers and limit lines GPIB and RS-232 for instrument control Second GPIB for controlling an external local oscillator The Keysight N897xA Series are high performance noise figure analyzer designed to make fast, accurate and repeatable noise figure measurements. With the N897xA's ease of use features, you can set up complex measurements simply and easily giving you repeatable and reliable results you can trust. They offer simultaneous noise figure and gain measurements with the ability to view, print and save the data/display in multiple formats. They also have the ability to characterize amplifiers and frequency translating devices, including LO control over dedicated 2nd GPIB.