This application measures the optimum Gamma that provides the maximum delivered power for nonlinear devices. Unlike classic S-parameters, which capture only linear device behavior and ignore nonlinear behavior, X-parameter terms (Xf, Xs, Xt) are used to predict the Gamma that yields the optimum power delivered to a load from a nearly matched device under large-signal drive and thus define the nonlinear behavior of the DUT.
The X-parameter terms assume the following:
In this topic:
Proper corrections for matched amplifiers operating in nonlinear (Compression, Saturation) region by using fundamental X-Parameters measurements (XS, XT, XF) of the DUT.
Ensures system-to-system correlation across different test stands.
Provides fast measurements of the Hot S22, Hot S21 of the DUT.
Easy calibration and measurement setup. Comb generator is not needed for calibration.
Provides measurements of the optimum match for maximum delivered power and the value of the maximum power, as well as, power delivered to 50 ohms.
Uses X-parameter technology to solve the
non-linear X-parameter equation (restricted to 50 GHz for option 111):
For
option 111, characterization above 50 GHz uses active source injection
at device input and output to solve the traditional linear S-parameter
equation:
Active Hot Parameter software for “A” model PNA-X (N524xA)
110, Active Hot Parameters
111, Active Hot Parameters, restricted to 50 GHz
4-Port PNA-X with 2 sources
On the PNA front panel, press Meas > Measurement Class....
Select Active Parameters, then either:
OK delete the existing measurement, or
New Channel to create the measurement in a new channel.
An Active Parameter measurement is displayed.
Configure Active Parameter settings |
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Using front-panel
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Using a mouse |
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Sweep Type - Sets the sweep type to the active 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 you specify. Learn about power sweep. Multisweep Selects multiple sweep. This is also called 3D sweep (power, phase, and frequency). Each sweep can be set to a different power level. Within each sweep is a 2D sweep of phase and frequency. With a fixed input power, a frequency-swept trace is useful to analyze the DUT’s frequency response. With fixed input power and fixed frequency, offset-phase measurements are performed to get adequate values to compute the “active S22” and X parameters. Linear/Log Frequency Sweep Type Source
Power Sweep Sweep Type Source
Multisweep Sweep Type Source
Extraction
Extraction Tone (ET) Level The level of the extraction tone must be small enough to ensure a spectrally-linear response, but large enough to ensure that the response is measurable. A Source Power Cal is performed and both the LSOP (large signal output power) and Extraction tones power levels are adjusted to compensate for loss, external amplifiers, and attenuators. Select the method used to set the ET Power Level: The goal of both of the Absolute and Relative ET Level methods is to set the ET level ~16 dB below the LSOP level while ensuring a spectrally-linear response from the DUT.
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Power On - all channels - Check to enable source power for all channels. Source
Extraction
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This tab allows the user to select a subset of the data to be displayed on the screen (frequency, power, phase) by defining the x-axis and a set of fixed values for the other parameters. Active Selects a trace to be active. A trace must be active before its trace settings can be changed. Select all traces Check to select all traces. X-axis display Sets the x-axis sweep type. Frequency
Power
Phase
DC
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This dialog is identical to the X-axis tab above. Access this dialog by right-clicking in the trace status area then selecting Active Parameter Analysis...:
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How to select and configure Measurement Parameters |
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Using Hardkey/SoftTab/Softkey |
Using a mouse |
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Option 110 Measurement Parameters Note: In the example below, Port 1 is the Source Port (DUT input) and Port 3 is the Extraction Port (DUT output). Port 3 or Port 2 can be chosen as the output of the DUT.
Option 111 Measurement Parameters IPwr Check to measure input power. OPwr Check to measure output power. HotS31 Check to measure Active Gain. HotS33 Check to measure Active Output Match. HotS13 Check to measure Reverse Isolation. HotS11 Check to measure Active Input Match. Gamma Check to measure optimized Gamma. Pmax Check to measure maximum delivered power. Xs(3,3), Direct Reflection Coefficient. The fundamental XS33 parameter which is used, in combination with XT22, to describe the change in b2 as a function of a2, the signal reflected from the load. Xt(3,3), Direct Reflection Coefficient. The fundamental XT33 parameter which is used, in combination with XS22 to describe the change in b2 as a function of a2, the signal reflected from the load. Xf(3,1), Output Coefficient. The fundamental XF31 parameter. DeltaOPwr Check to measure the delta between the output wave and output power to Z0 load.
Available for option 111 only (the following traces are not restricted to 50 GHz) HotGain Check to measure forward gain using linear S-parameters output/input. HotMatch Check to measure active output match using linear S-parameters.
Buttons Select All Click to select all measurement parameters. Clear All Click to deselect all measurement parameters. Create in New Window Check to create a new trace in a new window for the measurement. Channel Number Select a channel number for the measurement.
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A calibration can be performed on the Active Parameter Channel using the Cal All Wizard.
The data can be saved to a *.csv file with a column for each measurement parameter.
How to save data |
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Using front-panel
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Using Menus |
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