How to perform a Cal All Channels Calibration
Using Hardkey/SoftTab/Softkey
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Press Cal > Call All...
"Cal All" allows you to calibrate multiple channels in a single calibration session. This not only reduces the number of connections that need to be made, but also the number of cal standard measurements that must be performed.
In this topic:
Note: Call All is disabled when one and more M9377A are installed.
Cal All offers a single, optimized calibration procedure for all channels (with some limitations, see below). The optimizations include:
Minimizing the number of physical connection of standards.
Minimizing the number of power meter calibration sweeps.
User-settable power levels for S-Parameter as well as power calibration steps.
Accounting for different switch and attenuator settings among different channels. This reduces the number of measurements required to characterize different switch/attenuator settings (channel setup differences).
Cal All will produce the same number and format of Cal Sets (error terms) that would be realized had the calibrations been performed one at a time.
SMC+ Phase with phase enabled is supported using a known delay mixer or a phase reference cal set. S2P file characterized mixers are NOT supported.
Starting the VNA in Multiport mode is NOT supported.
Cal All is performed at one IFBW.
All channels that are calibrated are forced into stepped sweep mode.
All channels to be calibrated MUST have the same cal reference plane. In other words, Cal All cannot compensate for any path changes that occur external to the VNA.
How to perform a Cal All Channels Calibration |
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Using Hardkey/SoftTab/Softkey |
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Note: To perform an LO power cal for a mixer channel, set the LO port to a VNA or external source in the Mixer Setup dialog. Then select that port in this dialog. Note: In M9485A, Only ports 1 to 4 can be set even if your unit has more than 4-port configuration. |
Confirm or change the following unique cal properties for each channel to be calibrated. Click a link to learn about these properties. The properties with (NOT available in Cal All) are NOT available in a Cal All calibration as they are in a stand-alone calibration. Gain Compression
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Programming |
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UI Setting |
Property |
Value |
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Enable Phase Correction |
"Enable Phase Correction" |
"true" or "false" |
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Phase Correction Method |
"Phase Correction Method" |
"Use Mixer Delay" "Use Receiver Characterization Calset" |
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Mixer Delay |
"Mixer Delay" |
Real number indicating delay value. |
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Receiver Characterization Cal Set |
"Calset" |
String of Cal Set Name |
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Characterized mixer (s2p file) |
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Programming |
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UI Setting |
Property |
Value |
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"Include Power Calibration" |
"true" or "false" |
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The power cal is optional only if none of the selected channels require a power cal.
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This dialog shows the Power, Attenuator, and IFBW settings for the Cal All calibration. The default values for the Cal All session are the preset values of a standard S-parameter channel. These values are not necessarily the same as those of the channels that are selected for calibration. When there are differences in measurement path (switch) settings between the Cal All channel and the selected channels, these differences are detected by Cal All and additional measurements are made for each path condition. These additional measurements allow Cal All to produce error terms appropriate for each of the selected channels. In general, the Cal All session should be performed at a power level that is high enough to prevent noise in the error terms. However, an increase in power could cause compression or damage to the VNA receivers. The following settings allow you to increase the power level ONLY during the Cal All session. Power Limit (Disable) Cal All shows you when power limits are enabled. This setting provides you a convenient way to TEMPORARILY disable these limits in order to take advantage of the power settings available in Cal All. If power limits are on, your DUT is probably a high-gain device and the attenuator settings in your channels are high resulting in lower power at the cal reference plane. This lower signal can result in noisier measurements during the acquisition of cal. This situation is precisely what Cal All is intended to improve. Cal All allows you to configure the calibration conditions for better signal-to-noise performance during the cal while leaving your DUT conditions alone. You can elect to clear the “Disable Power Limits during cal” checkbox when you prefer to calibrate at a higher power level than is allowed by your limit. The limit is restored after the Cal All session. Source / Receiver Attenuator Note: M9485A does not support this function By default, the Cal All calibration is performed with Source and Receiver attenuators set to 0. Change the Source or Receiver attenuator settings when external hardware (such as a booster amplifier) would cause the VNA receivers to be compressed or damaged. You may also want to change the attenuator or path configuration settings to force the cal channel to match settings of the selected channels. If all of the selected channels are set to identical hardware settings, it may be better to apply these settings to the cal channel. For example, if your channels all use a 5 or 10 dB attenuator step at port 1, you might elect to change the Cal All channel to use the same low attenuator settings. This will result in the cal measurements being made under the same path conditions as the channel and it will eliminate the need to mathematically compensate for the difference. However, if large attenuator values are used, the default Cal All settings will likely improve your results. S-Parameter Cal Port Power Set the power level at which the S-Parameter cal is performed. Power Offsets Power Offsets are channel-scoped. Consequently, offsets that you already set are NOT automatically copied to the Cal All session. This setting allows you to also apply a Power Offset during the Cal All session. Learn about Power Offsets. Set the IFBW used to perform the Cal All calibration. The default IFBW setting of 1 kHz is a good nominal setting for most measurements. Lowering the IFBW removes noise from the calibration measurement, but also causes slower sweeps. Note: M9485A/E5080A does not support this function In addition to application-specific calibration requirements, Cal All performs an S-parameter calibration + power cal on behalf of all the selected channels. By default, this calibration is performed with standard channel default hardware paths:
Path configuration differences between your channel and the Cal All channel are mathematically removed. The Path Configuration dialog allows you to change the path settings for this portion of Cal All calibration. |
For each DUT port:
Check Modify Cal to change the Thru method. An Unknown Thru cal is performed by default. Learn about THRU methods. |
A guided power cal is performed on the source ports for the Cal All calibration. This dialog is displayed for each source port to receive a power cal. To perform an LO power cal for a mixer channel, set the LO port to a VNA or external source in the Mixer Setup dialog. Then select that port in the Selected Channels dialog.
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This page is a summary of the Cal All settings. Confirm the settings, then click Next > or < Back to change settings. |
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Follow the prompts to connect each standard. Then click Measure. Click Re-measure if necessary. Then click Next >
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Click Finish to save the Cal All session results to Cal Registers. Or click Save As User CalSet, then enter a prefix title. The Meas Class and channel number are appended to this prefix to save to a User Cal Set for each calibrated channel.
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Last modified:
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18-May-2016 |
First Release |
