Instructions

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stops the scan operation. A scan can not be paused, once aborted the data is lost
and it must be run again from the start.
8.2.3.1 The Scan Display
When a scan is completed, or when a stored scan is recalled, the graticule area shows an
overview of the complete scan in light blue. In addition, the area directly below the graticule
shows a vertically compressed version in light grey.
Unlike the normal sweep display which shows a
single level for each display point, the scan display
is an envelope created by drawing a vertical line
between the highest and lowest level found for the
block of frequency samples represented by each
display point.
A single yellow marker appears in the centre of
graticule along with a frequency readout directly
below. The frequency represents the centre of the
block of frequencies represented by the display
point. No level is shown.
When the display is zoomed to show more detail,
the lower area continues to show the full scan, with
the zoomed area represented by a grey box. The
marker position is shown in green on the lower
display.
In the example shown, the span has been set to
165MHz and the RBW to 30kHz, generating a scan
of 16,501 points.
The zoom has been set to level three giving a
graticule scaling of 2.16MHz per division
(21.6MHz of the span shown within the graticule area, centred around 229.4MHz).
For this particular scan, the maximum zoom level would be six, giving a scale of 0.27MHz per
division (27 x RBW/3). When this is reached the trace colour changes to green and, because
each display point represents a single data point within the scan, a marker level is displayed.
8.2.3.2 Viewing a Scan and using the Marker
Zoom and Pan enables the scan to be observed in detail.
the zoom operates around the position of the marker. Initially the total
number of samples in the scan is displayed, but each zoom step shows a
number of samples which is a binary multiple of 271.
For example, for a scan of 12,000 points, the first level of zoom would be to 8,672 points, then
4,336 points – eventually ending at 271 points (zoom step 6).
The compressed display continues to show the full scan with the zoomed area indicated by a
grey rectangle behind it. The zoomed graticule scaling is shown in the lower annotation area as
Scale: nnn.nnnn MHz/div.
this key is a shortcut to the maximum available zoom (a display of the 271 samples
around the marker position). At maximum zoom, each display point represents a
single sample and has a single level value associated with it.
At maximum zoom the display colour changes from light blue to green, and the level at the
marker position is displayed in addition to the frequency.
Zoom/
Pan
Abort
Scan
Zoom
In
Zoom
Out
Max.
Zoom