Symmetricom 5120A User Manual

5120A/5115A Operations and Maintenance Manual 37
To place a marker using the mouse:
1. Right-click anywhere on the phase noise plot and select Markers > Place Marker or
Markers > Place
Δ Marker.
 Tip: These functions can be invoked by pressing the ‘M’ or ‘D’ key on a USB
keyboard.
 The mouse cursor changes to a cross hair as shown above the delta marker in
Figure 10 Example Phase Noise Data with Data Markers.
2. Move the mouse.
 The marker follows the x-coordinate of the mouse cursor.
 Tip: Due to limitations imposed by screen resolution, multiple data points are plotted
at the same x-coordinate. Mouse-based marker placement also considers the y-
coordinate when selecting the best matched measurement. The mouse was used to
place the delta marker in Figure 10 Example Phase Noise Data with Data Markers.
Note that the cross hair mouse cursor is above the actual measurement traced by the
marker. This ensures that the marker is placed on the highest data point at that offset
frequency. If the mouse cursor was at the same x coordinate but below the data set, the
lowest point at that x coordinate would have been selected.
3. Click the left mouse button to position the marker.
To remove all markers and related information windows:
1. From the front panel, press Phase Noise Plot.
2. Press Config Phase Noise.
3. Press Markers.
4. Press Hide Markers.
 All markers and windows are removed from the screen.
Alternatively, right-click the phase noise plot at any time and select Markers > Hide. The marker
softkey interface need not be active.
Once a marker is placed at a frequency it will follow the measurement at the frequency closest to
it. This “best match measurement” is calculated every time new data becomes available. Consider
the following scenario to understand why this is relevant:
1. The test set has measured phase noise for 30 minutes and measurements at offset
frequencies below 10
-3
Hz are available.
2. A marker is placed at an offset frequency of 0.012 Hz.
3. Data collection is stopped and restarted. Phase noise data at 0.012 Hz will not be available
for some time. Until it becomes available, the measurement whose frequency most closely
matches that of the marker position is the measurement with the lowest offset frequency.
The marker follows this measurement. When a measurement at (or below) 0.012 Hz is
available the marker stops moving in frequency and begins to continually follow the 0.012
Hz measurement.
Note
Markers can also be placed on a specific spur’s frequency using the Spur Table. For more

Symmetricom 5120A Specifications

General

Brand	Symmetricom
Model	5120A
Category	Recording Equipment
Language	English