UNI-T UTS3000B/A Series User Manual page 42

FREQ
Press [FREQ] key to activate the center frequency function and enter the frequency menu. The
numerical value of center frequency, sweep span, start frequency and stop frequency are displayed
at the bottom of the screen.
Center Frequency: This function can set a specific frequency value at the center of the screen and
respectively display the center frequency and sweep span values at the left and right side on the bottom
of the screen. Use numeric key, direction key or touch panel menu to change center frequency.
Note

Under the premise of constant sweep span to change the center frequency, it will automatically
modify the start and stop frequency.

Changing the center frequency which is frequency shifting the current channel, the adjustable range
is limited by the frequency range listed in the technical specifications of the spectrum analyzer.

In zero span, start frequency, stop frequency and center frequency are the same.
Span: This function is to input range value of sweep span. Use numeric key, direction key or touch panel
menu to change sweep span. The sweep span will be changed symmetrically according to the center
frequency. The reading of sweep span is the total displayed frequency range. To determine the sweep
span for each horizontal scale division, the above sweep span should be divided by 10.
Note

Under the premise of constant sweep span to change the width sweep, it will automatically modify
the start and stop frequency.

In zero span, the minimum sweep span can set to 100Hz. When the sweep span is set to the
maximum, the spectrum analyzer enters full span mode.

Changing sweep span to 0Hz by manual setting or press zero span menu to enter zero span mode.

Changing the sweep span in non-zero span mode, if the stepped center frequency and RBW are
automatic, it will be modified automatically. The modification of RBW will cause the change of VBW
(in automatic).

A change in one of three sweep span, RBW and VBW will cause a change of sweep time.
Start/Stop Freq: Start frequency is on the left side of the screen, the right side is stop frequency. After
the frequency setting, it will display at the bottom of the screen, replacing the original displayed center
frequency and sweep span. Use numeric key, rotary knob, direction key or touch panel menu to change
the start frequency.
Note

Changing the start/stop frequency will cause the change of sweep span and center frequency, and
the change of sweep span will affect the parameter of other system.

In zero span mode, if start frequency, center frequency and stop frequency are the same, it will be
modified together.
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