Specifies the format of S-Parameter measurement.

Use "sparam<n>" as the selector string to configure or read this property.

The default value is Magnitude.

Remarks

The following table lists the characteristics of this property.

Short Name SParams Format
Data type ci32.png
Permissions Read/Write
High-level VIs N/A
Resettable Yes
Magnitude 0

Sets the format of the selected S-Parameter to Magnitude. You can specify SParams Magnitude Units.
Phase 1

Sets the format of the selected S-Parameter to Phase. Phase values are expressed in degrees. Phase can be represented in various, mathematically equivalent ways such as phase wrapped between the range [-180, 180) degrees, or phase can be represented in an unwrapped manner. You can specify the phase representation by configuring Sparams Phase Trace Type.
Complex 2

Sets the format of the selected S-Parameter as complex numbers in cartesian co-ordinates.
SWR 3

Sets the format of the selected S-Parameter to Standing Wave Ratio (SWR). SWR is a unitless quantity.
Smith Impedance 4

Sets the format of the selected S-Parameter to Smith Impedance. S-Parameter values are transformed into impedence values. Impedence values are expressed in ohms. You can use these values to plot on a Smith Chart.
Smith Admittance 5

Sets the format of the selected S-Parameter to Smith Admittance. S-Parameter values are transformed into admittance values. Admittance values are expressed in siemens. You can use these values to plot on an Inverted Smith Chart.
Polar 6

Sets the format of the selected S-Parameter as complex numbers in polar co-ordinates, where the radial axis (i.e., magnitude of the complex numbers) is always in linear scale and angular axis (phase) is represented in degrees and always wrapped between ±180 deg.
Group Delay 7

Sets the format of the selected S-Parameter to Group Delay. Group delay represents the time it takes for the signal to pass through a device under test. The delay is expressed in seconds.

Group delay vs. frequency is derived from phase vs. frequency response. At a given frequency point, group delay is computed by selecting two nearby frequency points and taking the ratio of the phase difference to the frequency separation between them. The frequency separation between the two selected points is called the group delay aperture.

You can control the aperture by first configuring SParams Group Delay Aperture Mode and once the mode is selected, you can set the aperture by configuring SParams Group Delay Aperture Points, SParams Group Delay Aperture Percentage or SParams Group Delay Aperture Frequency Span.

For example, if the number of aperture points is equal to 3, then group delay at a nth frequency point is computed by selecting the (n-1)th frequency point and (n+1)th frequency point.