PXIe VNA Help
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Scale

The Scale, Reference Level and Reference Position settings (along with Format) determine how the data trace appears on the VNA screen.

See other 'Setup Measurements' topics

Scale, Reference Level and Position

The Scale, Reference Level and Reference Position settings (along with format) determine how the data trace appears on the VNA screen.

How to set Scale, Reference Level, and Position

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Scale > Main > Scale / Reference Level / Reference Position.

  2. Input the desired value.

  1. Right-click on Y-axis annotation or the trace status label above the grid box.

  2. Select Scale....

 

Scale dialog box help

Note: The scale settings are set to couple with other traces in each window. The following settings assume that Scale Coupling is set to OFF. Learn more about Scale Coupling.

Scale

Per Division  Sets the value of the vertical divisions of a rectangular display format. In Polar and Smith Chart formats, scale sets the value of the outer circumference. Range: 0.001dB/div to 500 dB/div.

Tip: Click on the Y-axis labels, then use a mouse scroll wheel to change scale in preset increments. Or Right-click on Y-axis annotation to change Scale.

Autoscale - Automatically sets value of the vertical divisions and reference value to fit the ACTIVE data trace within the grid area of the screen. The stimulus values and reference position are not affected.

The analyzer determines the smallest possible scale factor that will allow all the displayed data to fit onto 80 percent of the vertical grid.

The reference value is chosen to center the trace on the screen.

Tip: Double click on the Y-axis labels to autoscale the active trace.

Autoscale All  Automatically scales ALL data traces in the ACTIVE WINDOW to fit vertically within the grid area of the screen.

Reference

Level  In rectangular formats, sets the value of the reference line, denoted by on the screen. Range: -500 dB to 500 dB.

In Polar and Smith chart formats, reference level is not applicable.

Tip: Click on the Y-axis labels, then drag up or down to change the reference level in preset increments.

Position  In rectangular formats, sets the position of the reference line. Zero is the bottom line of the screen and ten is the top line. Default position is five (middle).

In Polar and Smith chart formats, reference position is not applicable.

Tip: Click on the triangle , then drag up or down to change the reference position in preset increments.

Scale Coupling

With Scale Coupling enabled, traces that have the same format will have the same Scale, Reference Level, and Reference Position. You can choose to couple the scale of traces that are in the same window, couple the scale of all traces in all windows, or to have NO coupling.

How to set Scale Coupling

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Scale > Main > Scale Coupling....

  1. Right-click on Y-axis annotation.

  2. Select Scale Coupling....

 

Scale Coupling dialog box help

Allows traces that share the same format to have the same Scale, Reference Level and Reference Position.

Coupling Method

Off - No coupling. Traces are scaled individually. Default setting.

Window - All traces with the same format in each selected window share the same scale settings.

All - All traces in ALL selected windows with the same format share the same scale settings.

  • When Window or All coupling is enabled, the scale settings for the active trace are assumed by other coupled traces with the same format.

  • When there are traces with a different format present, all traces with that format assume the trace settings of the lowest-numbered trace of that format.

  • Once enabled, scale settings for all coupled traces with the same format can be changed with any coupled trace being active.

Selected Windows

Available when either the Window or All method is selected. Selected windows will participate in scale coupling. All windows are selected by default. Clear a checkbox to 'Opt-out' of scale coupling for that window.

About Autoscale and Scale Coupling

Autoscale (not Autoscale All) affects the active trace in the active window. All traces that are coupled to this trace assume the new scale settings of the active trace. This could cause some traces to NOT show on the screen.

Autoscale All with Coupling Method...

  • Off - All traces in the active window are autoscaled independently.

  • Window - All traces in each selected window are autoscaled to fit within a common set of scaling factors.

  • All - All traces in all selected windows are autoscaled to fit within a common set of scaling factors.

 

Y-Axis Graph (Lin/Log Scale), Top, Bottom, Ref X/Y Level, Ref X/Y Position

How to set Y-Axis Spacing

Using Hardkey/SoftTab/Softkey

  1. Press Scale > Main > Y-Axis Spacing / Top / Bottom / Ref Y Level / Ref Y Position / Ref X Level / Ref X Position.

Y Axis Spacing - Selects either a linear or log scale Y-axis format.

Top - Sets the maximum scale value for the Log Y-axis.

Bottom - Sets the minimum scale value for the Log Y-axis.

Ref Y Level - Sets the Y axis Reference Level of the specified trace in the specified window.

Ref Y Position - Sets the Y axis Reference Position of the specified trace in the specified window.

Ref X Level - Sets the X axis Reference Level of the specified trace in the specified window.

Ref X Position - Sets the X axis Reference Position of the specified trace in the specified window.

Graph Area Graticules

In the graph area, multiple traces can be drawn overlaid. Different graticule is drawn based on the active trace.

The following is an example of a case that these 3 traces are shown:

Trace 1 = Log ( 10k to 1M )

Trace 2 = Log ( 5k to 500k )

Trace 3 = Linear

When trace 1 is active.

When Trace 2 is active (graticule is still log, but different from Trace 1)

When Trace 3 is active.

Magnify Mode and Zoom Preference

The magnify feature allows to magnify all traces in the active window. It allows to zoom into a portion of the display to see the response in detail.

How to magnify the trace

Using Hardkey/SoftTab/Softkey

Using a mouse

None

  1. Left-click and select the area you want to magnify

  2. Select Magnify from the pop-up menu.

Other methods to set the magnify mode includes:

When the Magnify Mode is turned on:

2-finger pinch on the display changes the x and y magnification. If magnification is pinched down to 1:1 scaling, the magnify mode will be turned off.

1-finger drag across display changes  the reference of the magnified x and y.

 

Zoom Preference Dialog Box Help

Zoom Preference allows you to decide the default operation of the 2-finger pinch gesture, from these 4 choices:

2-finger pinch automatically turns on magnify mode so that x and y-axis can be magnified/ This is the default setting.

2-finger pinch changes y-axis scale.

2-finger pinch changes y-axis scale and x-axis stimulus.

2-finger pinch does nothing.

Magnitude Offset

Magnitude Offset allows you to offset the magnitude (not phase) data by a fixed and / or sloped value in dB. If the display format is Linear Magnitude or Real (unitless), the conversion from dB is performed and the correct amount of offset is implemented.

How to set Magnitude Offset

Using Hardkey/SoftTab/Softkey

  1. Press Scale > Constants > Mag Offset / Mag Slope.

 

Magnitude Offset dialog box help

Magnitude Offset allows you to offset the magnitude (not phase) data by a fixed and / or sloped value in dB. If the display format is Linear Magnitude or Real (unitless), the conversion from dB is performed and the correct amount of offset is implemented.

The Magnitude offset setting affects only the active trace.

Mag Offset  Offsets the entire data trace by the specified value.

Mag Slope  Offsets the data trace by a value that changes with frequency. The offset slope begins at 0 Hz.

For your convenience, the offset value at the start frequency is calculated and displayed.