Tektronix MSO46 — understanding Spectrum Time Width and Position in Signal Analysis [175/628]

The Spectrum Time width (amount of the acquisition record) is determined by the FFT Window factor divided by Resolution

Bandwidth (RBW). Changing the FFT window type and/or the RBW parameters changes the Spectrum time width.

The Spectrum Time position can be moved through the time domain acquisition using a variety of methods including tapping and

dragging it, using the Wave Inspector Pan knob, or with the Spectrum Time position control in the Spectrum configuration

menu.

The FFT Window, RBW, and Spectrum Time settings are in the Spectrum menu (see Spectrum badge menu on page 426).

The Spectrum Time Bar is shown whenever a Spectrum View trace is enabled for a channel.

Example use of Spectrum Time to determine the time to a stable signal.

This example shows the use of Spectrum Time to determine the time for a spread spectrum (SS) clock to become stable after

power-up. The clock signal is centered around 98.5 MHz.

An acquisition was taken with a long enough time setting to ensure that the SS clock signal had stabilized. The RBW was set to

500 Hz, and the Spectrum Time position was set to just before the SS clock signal became stable. See the following image.

Using Spectrum View

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