Analyzer Settings

The Analyzer Settings softkey determines the frequency range that is measured and displayed and the resolution bandwidth of the spectrum analyzer.

The settings are specific to the Spectrum menu. Some of them are also provided in the Control tab of the Spectrum Configuration menu; see section Measurement Configurations (Spectrum Configuration).

A single measurement of the signal power over the whole frequency range (span, sweep width) by means of a spectrum analyzer is called a sweep. Typically, the minimum sweep time T_min is linked to the resolution bandwidth B of the analyzer and the frequency range F by the relation T_min ~ F/B². This means that a compromise between a high resolution, wide frequency range and high measurement speed must be reached.

The frequency range can be set in three different ways:

• By defining the center frequency f_c and the span Df. The start and stop frequencies are thus given by f_start = f_c - Df/2 and f_stop = f_c + Df/2. This mode is convenient if the spectrum is to be analyzed in the vicinity of a known frequency which can be used as the center frequency of the diagram.
• By defining the start frequency f_start and the stop frequency f_stop. The center frequency and span are thus given by f_c = (f_start + f_stop)/2 and Df = f_stop - f_start.
• By selecting Full Span the default frequency range is displayed, i.e. the default start and stop frequencies are selected.

The number of vertical grid lines (i.e. the number of cells in horizontal direction) can be variable (depending on the frequency span) or fixed, see Spectrum Configuration menu.