Marker Search Operations
Marker search operations quickly move a marker to specific points on the active trace. Selecting an item from this menu enables a marker for the active trace when a marker has not yet been added or is not visible.
Some marker search operations behave differently for OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. traces which contain Z-axis data in addition to X and Y-axis data. This is noted in the following descriptions.
The marker can also be moved to a target value by editing the Marker Position display annotation below the trace. The target value is always absolute, regardless of whether the marker is a delta marker (a delta marker uses the underlying marker's magnitude instead of the calculated offset when doing a search operation).
The "next peak" must be at least one display point away from the marker's current location. If the VSA doesn't find a peak, the marker does not move.
Generally, the best way to change the number of peaks found is to average several measurements to reduce noise variance.
|
Search function |
Description |
Shortcuts |
|---|---|---|
 Peak |
Moves the active marker to the highest point on the active trace.
The VSA can automatically move the marker to the highest point each time the trace is updated (i.e. when a measurement is running). To enable this feature (called peak tracking), select the Peak Track check box in the Markers Position dialog box. |
Page Up key Or, right-click in the trace and select Peak from the menu. |
 Peak Higher |
Moves the active marker to the next higher peak on the active trace. The algorithm goes through the whole trace and analyzes all peaks, then moves the marker to the peak with the next higher value compared to the current marker value. A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again. With the polar (IQ) data format, moves the marker to the closest point that has a higher magnitude than the marker's current position. OFDM traces: moves the marker to the next higher Y-value along the Z-axis for the current X-axis position. This operation will not move the marker in the X-axis dimension. |
up arrow key |
 Peak Left |
Moves the active marker left, to the next valid peak. A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again. This function is useful if the marker is close to a peak and you want to fine-tune the marker position to the peak. If the polar (IQ) data format is selected, the next is the previous point (back in time) with a higher magnitude. OFDM traces: moves the marker to the left by one X-axis point to the Z-axis point that has the nearest Y-axis value to the current Y-axis value. |
Ctrl + left arrow key |
 Peak Right |
Moves the active marker right, to the next valid peak. A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again. This function is useful if the marker is close to a peak and you want to fine-tune the marker position to the peak. If the polar (IQ) data format is selected, the next is the next point (forward in time) with a higher magnitude. OFDM traces: moves the marker to the right by one X-axis point to the Z-axis point that has the nearest Y-axis value to the current Y-axis value. |
Ctrl + right arrow key |
 Peak Lower |
Moves the active marker to the next lower peak on the active trace. The algorithm goes through the whole trace and analyzes all peaks, then moves the marker to the peak with the next lower value compared to the current marker value. A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again. With the polar (IQ) data format, moves the marker to the closest point that has a lower magnitude than the marker's current position. OFDM traces: moves the marker to the next lower Y-value along the Z-axis for the current X-axis position. This operation will not move the marker in the X-axis dimension. |
down arrow key |
 Minimum |
Moves the active marker to the lowest point on the active trace. The lowest point is the point with the smallest y-axis value. If the polar (IQ) data format is selected, the lowest point is the point with the smallest magnitude. |
Page Down key |
