The third and last step of preparation for a distortion test takes place in the Setup Dialog of the Test Panel. In a single-frequency distortion test, the frequency of the designated AC source is swept from the Start Frequency to the Stop Frequency on a linear, decade or octave scale. Similar to the AC Frequency Sweep test, depending on the scale (Interval Type) chosen, you have to set either the Frequency Step or Number of Steps per Interval. For a two-frequency distortion test, you must check the checkbox labeled "Use F2/F1" and then enter a value for the ratio. Note that this ratio must be between 0 and 1. In this case, the analysis considers the circuit with sinusoidal inputs at two different frequencies, F1 and F2. F1 is swept according to the SPICE's DISTO control line options in the input Netlist file. The frequency of the second source F2 is kept fixed at (F2/F1) times the Start Frequency. Each independent source in the circuit may have up to two sinusoidal inputs for distortion at F1 and F2 frequencies. The analysis provides results composed of all node voltages and branch currents at frequencies of F1, F2, F1+F2, F1-F2, and (2*F1)- F2.
{{Note | The main difference between B2[[RF.Spice]]'s Distortion Test and its Distortion Meter virtual instrument is that the former is used to plot or tabulate the the second and third harmonic contents of a signal over a frequency range, while the latter plots the harmonic contents up to the fifth harmonic as well as the "Total Harmonic Distortion" at a single specified frequency in the form of a bar chart.}}
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[[File:b2MAN_Fig232.png|thumb|470px|The output of a Small-Signal Transfer Function Test.]]
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===Small-Signal Transfer Function Test===