GW Instek GSP-810 User Manual User Manual

Page 18

GSP-810 User Manual

MARKERS

The GSP-810 supports 2 markers. To access the marker screen, press the MRK

key. Displayed will be 2 marker frequencies. Accessing the marker frequency

fields is performed through the left column of numbers. Cursor to the left most

position, then use the SPINNER to switch between marker 1 and marker 2.

Pressing ENTER will also switch between the 2 marker fields. The frequency

value may be changed by entering the digits, decimal point, followed by the

ENTER key, or the

Í and Î keys can select a digit within a marker to increment

or decrement by using the SPINNER. The valid range of entries is 0.000 MHz to

1150.000 MHz.

A marker will appear on the CRT when the marker frequency selected falls within

the range of frequencies defined by the main screen Center Frequency and Span.

For example, if the center frequency selected is 100.000 MHz and the span is 1

MHz per division, a marker will appear on the screen if the marker frequency is

anywhere between 95 MHz and 105 MHz. When the marker is displayed on the

CRT, the signal level at the location of the marker will be displayed to the right of

the marker frequency. This level will continuously update while in the marker

screen. If the marker frequency is outside the range of frequencies for a given

Center Frequency and Span, a message will indicate its status. If the marker

frequency is too high to be displayed on the CRT, instead of the marker level, “Off

(high)” will be displayed. If the marker frequency is too low, then “Off (low)” will be

displayed. If the Markers are disabled, then “OFF” is displayed. To disable the

markers, simply press the Marker key while in the markers sub-screen.

If the markers are enabled, their position on the CRT will be updated on each

Center Frequency change and each Span change. If a Center Frequency or Span

is selected such that the marker moves off the CRT screen, they will be off until the

parameter is changed to allow the marker to re-appear.

The resolution of the marker on the screen is based on the span selected. There

are 50 positions between major divisions on the CRT that a marker can be moved

to. In the 100 MHz/div Span, for example, every 2 MHz will move the marker 1

position. On the outside edges of the trace, however, the maximum and minimum

marker positions are considered out of range.