single-sweep mode

The analyzer sweeps once when trigger conditions are met. Each sweep is initiated by pressing an appropriate front-panel key, or by sending a programming command.

sinusoid

A wave whose electric-field vector is proportional to the sine (or cosine) of an angle that is a linear function of tune, or distance or both.

softkey

Key labels displayed on a screen or monitor which are activated by mechanical keys surrounding the display, or located on a keyboard. Softkey selections usually evoke menus that are written into the program software. Front-panel key selections determine which menu (set of softkeys) appears on the display.

span

Span equals the stop frequency minus the start frequency. The span setting determines the horizontal-axis scale of the analyzer display.

span accuracy

The uncertainty of the indicated frequency separation of any two signals on the display.

spectral purity

See noise sidebands.

spectral component

One of the sine waves comprising a spectrum.

spectrum

An array of sine waves differing in frequency and amplitude. They are properly related with respect to phase and, taken as a whole, constitute a particular time-domain signal.

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