Combined vector network and spectrum analysis capabilities. The frequency covered is from 10 Hz through 500 MHz with 0.001 Hz resolution for audio, baseband, HF, VHF, and IF applications. It directly measures amplitude ratio, phase, group delay, and spectrum level needed for characterizing linear/non-linear analog circuits or components. A color display allows you to readily differentiate among multiple traces. A built-in 3.5 inch disk application can save the instrument state, data and user functions. With the optional 41951A Impedance Test Kit, you can measure Z, Y, Phase, R, X, G, B, L, C, D, Q(1/D). GPIB.