A sweep is a series of consecutive data point measurements taken over a specified sequence of stimulus values. You can make the following sweep settings:
Number of Points (Separate topic)
Frequency Range: Start/Stop (Separate topic)
See Triggering and other 'Setup Measurements' topics
How to set Sweep Type |
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Using Hardkey/SoftTab/Softkey |
Using a mouse |
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Sweep Type Dialog Box / Sweep > Main > Sweep Type Softtab Help |
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Note: Sweep Settings are not applied until either OK or Apply is pressed. Channel - The active channel when Sweep Type was selected. Sweep settings will be applied to this channel.
Linear Frequency - Sets a linear frequency sweep that is displayed on a standard grid with ten equal horizontal divisions.
Log Frequency - The source is stepped in logarithmic increments and the data is displayed on a logarithmic X-axis. This is usually slower than a continuous sweep with the same number of points.
Power Sweep - Activates a power sweep at a single frequency that specify. Learn more about power sweep
CW Time - Sets the VNA to a single frequency and the data is displayed versus time. Learn more.
Segment Sweep - Sets the VNA to sweep through user-defined sweep segments. Learn how to make these settings. OK - Applies setting changes and closes the dialog box. Cancel - Closes the dialog. Setting changes that have been made do not apply and save, but it remain setting since the last Apply button is clicked. Apply - Applies setting changes and leaves the dialog box open to make more setting changes. Help - Display the Sweep Type dialog box help. |
A power sweep either increases or decreases source power in discrete steps. Power sweep is used to characterize power-sensitive circuits, with measurements such as gain compression.
In the Sweep Type dialog, specify Start Power, Stop Power, CW Frequency, Points and IF Bandwidth.
The remaining power settings apply in power sweep mode:
Test Port Power setting is not available.
Port Power can be coupled or uncoupled.
Power Slope (dB/GHz) is ignored (output frequency is CW).
Press Sweep > Main > Number of Points to change the step size of the power sweep.
Notes:
Power Sweep has been optimized for speed. For highest measurement accuracy during a power sweep, it may be necessary to increase the Dwell Time to allow the source more time to settle.
Segment Sweep activates a sweep which consists of frequency sub-sweeps, called segments. For each segment can define independent power levels, IF bandwidth, IF bandwidth per port, sweep time, delay.
Once a measurement calibration is performed on the entire sweep or across all segments, measurements can be calibrated for one or more segments.
In segment sweep type, the analyzer does the following:
Sorts all the defined segments in order of increasing frequency.
Measures each point.
Displays a single trace that is a composite of all data taken.
Restrictions for segment sweep:
The frequency range of a segment is not allowed to overlap the frequency range of any other segment.
The number of segments is limited only by the combined number of data points for all segments in a sweep.
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Segment Table Dialog Box Help / Sweep > Segment Table Softtab Help |
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Add Segment - adds a sweep segment at last segment. Insert Segment - adds a sweep segment before the selected segment. You can also click the "down" arrow on your keyboard to quickly add many segments. Delete Segment - removes the selected segment. Delete All Segments - removes all segments. Note: At least ONE segment must be ON or Sweep Type is automatically set to Linear.
Segment Table dialog box X-Axis Point Spacing - Check to scale the X-axis to include only the segments. Learn more. Allow Arbitrary Segments - Check to allow arbitrary frequencies (overlapped or reverse sweep). Learn more. Display Center/Span Freq - Check to display the center/span frequency.
Independent Setting Per Segment Power Level - Sets the Power level for the segment. Also, the test port power can UNCOUPLE. See Power Coupling. IF Bandwidth - Sets the IF Bandwidth for the segment. IF Bandwidth Per Port - Sets the different bandwidth with different port for the segment. Sweep Time - Sets the Sweep time for the segment. Delay - Sets the time to wait just before acquisition begins for each segment. Dwell - Specifies the time the source stays at each measurement point before the analyzer takes the data. Receiver Atten Per Port - Sets the receiver attenuators by logical receiver notation. Options are 0dB and 35dB. Default setting is 35dB.
Save Table - Saves the setting changes in segment table. Load Table - Apply the setting changes in segment table.
To Modify an Existing Segment To make the following menu settings available, the segment table must shows first. (Press Sweep > Segment Table)
The above graphic shows the Segment table with all independent settings selected, including source power uncoupled (two power settings). State - Click the box on the segment to be modified. Then, use the up/down arrow to turn the segment ON or OFF. Start - Sets start frequency for the segment. Click the box and type a value and the first letter of a suffix (KHz, Mhz, GHz). Or double-click the box to select a value. Stop - Sets stop frequency for the segment. Click the box and type a value and the first letter of a suffix (KHz, Mhz, GHz). Or double-click the box to select a value. Note: The segment table truncates the frequency resolution. To verify the frequency resolution that you input, create a marker at the start or stop frequency settings. Points - Sets number of data points for this segment. Insert a value or double-click the box to select a value. To set Power Level, IF Bandwidth/IF Bandwidth Per Port, Sweep Time, Delay, Receiver Attenuator Per Port independently for each segment:
Note: If the following are NOT set, the entire sweep uses the channel IFBW, Power, and Time settings. |
This feature affects how a segment trace is drawn on the screen.
Without X-axis point spacing, a multi-segment sweep trace can sometimes result in squeezing many measurement points into a narrow portion of the X-axis.
With X-axis point spacing, the X-axis position of each point is chosen so that all measurement points are evenly spaced along the x-axis.
For example, given the following two segments:
Without X-Axis Point Spacing
With X-Axis Point Spacing
This feature allows arbitrary frequencies to be entered into the segment sweep table. With this capability, segments can have:
Overlapping frequencies.
The stop frequency less than the start frequency (reverse sweep).
However, there are several limitation:
Sweep mode: Stepped only.
Sweep time: When reverse sweep is performed, the sweep time and the wait time before the measurement point becomes longer.
Notes:
Unusual results may occur when using arbitrary sweep segments with markers, display, limit lines, formatting and some calibration features.
When the segment table has both forward and reverse frequency sweep, the correction interpolation may not work properly. Use the same segment table setting at both, correction and measurement. (Make a measurement at the condition where "Cor" is displayed.)
When the number of data of segment table exceeds its limitation, the error occurs. In this case, reduce the measurement data size (i.e. NOP, number of channels).
The VNA automatically maintains the fastest sweep time possible with the selected measurement settings. However, you can increase the sweep time to perform a slower sweep.
How to set Sweep Time |
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Using Hardkey/SoftTab/Softkey |
Using a mouse |
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Sweep Time - Specifies the time the VNA takes to acquire data for a sweep. The maximum sweep time of the VNA is depends on various settings (ex, IFBW, Dwell Time, Number of points, etc). Learn about other settings that affect sweep speed. |
How to make Sweep Setup settings |
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Using Hardkey/SoftTab/Softkey |
Using a mouse |
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Time Sweep Time - same as Sweep Time Softtab Help. Dwell Time - Specifies the time the source stays at each measurement point before the analyzer takes the data. Only applies to stepped sweep. The maximum dwell time is 20 seconds. See also Electrically Long Devices. Sweep Delay - Specifies the time to wait just before acquisition begins for each sweep. This delay is in addition to Dwell Time (per point) and External Trigger delay if enabled. Auto Sweep Time - Automatic adjust the sweep time and dwell time. When "Auto Sweep Time" is checked, the sweep time and dwell time will disable to edit.
Sweep Mode Stepped Sweep - When clicked on Stepped Sweep Mode, the VNA source is tuned, then waits the specified Dwell time, then takes response data, then tunes the source to the next frequency point. This is slower than Analog Sweep, but is more accurate when testing electrically-long devices.
Standard Sweep - When checked, the VNA sweeps all data points for each source port in turn. For a 2-port VNA, this means that all data points are swept in the forward direction, then all data points are swept in the reverse direction. Even when NO reverse parameters are displayed (S22 or S12), reverse measurements are necessary when a full 2-port calibration is correcting the channel. This is the default behavior. Learn more. |
Last modified:
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18-May-2016 |
First Release |
