Calibrate All Channels

How to perform a Cal All Channels Calibration

Using Hardkey/SoftTab/Softkey

1. Press Cal > Other Cals > Cal All....

Selected Channels dialog box help

1. Check the channels to be calibrated.

2. Check the ports to be calibrated. Click on the Apply to all channels button to apply the port selections to all channels.

3. Click Next>

Measurement Class Cal Properties dialog box help

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.

ifferential IQ

Spectrum Analyzer

Gain Compression

GCX (Gain Compression Converters)

Noise Figure and NFX

Note: Calibrate All Channels for Noise Figure measurement channels is not supported on M980xA, M983xA, P50xxA/B, E5080B, E5081A instruments.

Swept IMD and IMDX

MOD (Modulation Distortion) and MODX (Modulation Distortion Converters)

SMC (VMC is NOT offered)

Standard Channel

The power cal is optional only if none of the selected channels require a power cal.

Setting Up an Independent Power Calibration

Independent Power Calibration

Several applications control internal and external sources in a mode that is often decoupled from the span over which the receivers are swept. This includes, for instance, Differential IQ, and Spectrum Analyzer. Cal All can add a power calibration for any port (including external sources) over an arbitrary frequency span defined by the user.

For all ports selected for an independent power calibration (except for Port 1 Src 2, see below), a power sensor calibration measurement is performed. The resulting source match correction terms are added to the calsets for ALL channels selected for the Cal All calibration. The power calibrations used in Cal All have all the same features as typical power calibrations. These include the ability to specify power offsets, the power at which the calibration is completed, and the ability to use multiple power sensors (note that using multiple power sensors is a feature only available on regular PNA ports – that is, not external sources or auxiliary ports).

Port 1 Src2 Calibration

The Port 1 Src2 calibration is a special case: In this case, a calibration is requested for situations where the Port 1 Bypass Switch is in “Combiner Path” mode and either the “Port 3 Bypass Switch” (4-port PNA-X) or the “Source 2 out 1 Bypass Switch” (2-port 2-source PNA-X) is also in “Combiner Path”. Therefore, if a user requests a calibration of this port:

1. Port 1 will also be calibrated at the same frequencies in the combiner path (*note:  The user can still elect to add more Port 1 independent cal ranges, but this will be done in “Bypass” mode, not “Combiner mode.”

2. The calibrations for both Port 1 and Port 1 Src2 will be done with both sources on, but offset by 10MHz (to more accurately characterize the behavior during use).

3. These calibrations will ONLY be applied to user channels in which both the Port 1 Bypass Switch and either the Port 3 or Source 2 Out 1 Bypass Switches are set to “Combiner Path.”

Important Notes:

• If a user selects an independent power calibration on a port also used for the typical S-parameter calibration, then the frequencies calibrated will be in addition to those frequencies used via the typical calibration (a separate measurement will be completed at the time).
• Previously a user could select a similar calibration of “LO” ports for application channels (for instance, in a GCX measurement with Port 3 used for LO1, a user can select (via GUI or remote) to do an “LO1” calibration.  This will do a power sensor calibration of LO1 (port 3) at the frequencies specified by the channel.  This is still available, but if the user selects to do an Independent Power Calibration instead, this will override the selection by the channel.

• If the user has a mixture of LFE (Low Frequency Extension) and non-LFE channels the calibration will be done by default in the NON-LFE configuration (this is because most applications do not support LFE and external sources and sources like Src2 Out 1 do not have LFE paths).  Instead, if it’s desired to do these calibrations in LFE mode, the user must select only LFE channels over which to do the cal all calibration.

• If setting up the calibration remotely, it is not necessary to set the power cal state for the extra power calibrations (for example, “SENS200:CORR:COLL:GUID:PSEN2 ON”). These state commands should only be used to specify the power cal port for the main calibration.

Independent Power Calibration for Cal All Setup

1. Start the Cal All Wizard.
2. In the Measurement Class Cal Properties dialog, enable Independent Power Calibration by selecting the port(s) to cal then clicking OK.

3. If Port 1 Scr2 is a selected port, the Port 1 Src2 Cal Power level is displayed allowing a calibration power level to be entered.

4. To enter the Port 1 Src2 Cal Power level, click in the field then enter a valid calibration power level.

5. In the Power Cal Settings for  Port<n> dialog, select the port from the Power cal at dropdown.
6. To add a new Cal range, click the New button.
7. Specify a frequency range for each Range Name by clicking in the corresponding Settings field then clicking on the Edit button that appears.

8. Enter the Start and Stop frequency and the number of Points then click OK.
9. Continue the Cal All process by clicking on the Next button.

Split Cal and Independent Calibration Channels

Beginning with firmware revision A.13.67.xx, there are two new attributes called Split Cal and Independent Calibration Channels that allow channels to perform their own calibrations.

Split Cal

The Split Cal applies to SMC and GCX channels. If selected, these channels will perform their own calibrations, performing two 1-port calibrations (no thru).

Independent Calibration Channels

The Independent Calibration Channels is a comma-separated channel list. Any selected channels will perform their own SmartCal instead of importing the calibration from the SmartCal performed on the special Cal All channel (typically Channel 200).

Note: Channels that do not support their own SmartCal cannot be Independent Calibration Channels. They will be filtered out if selected as Independent Calibration Channels.

Example of Cal All Process

The following is an example showing the typical Cal All process using three standard channels:

Ch 1: 1-2 GHz, 101 points

Ch 2: 2-3 GHz, 101 points

Ch 3: 3-4 GHz, 101 points

Cal All process without Independent Calibration Channel selections:

1. Creates a Cal All channel (typically Channel 200), which goes from 1-4 GHz, 303 points. 

2. Cal All tells the  Cal All channel to perform a SmartCal.

3. When the calibration is done, the SmartCal on the Cal All channel computes the error terms, and passes them to Ch1, Ch2, and Ch3.

Cal All process with channel 3 selected as an Independent Calibration Channel:

1. Creates a Cal All channel (typically Channel 200), which goes from 1-3 GHz, 202 points. 

2. Cal All tells the  Cal All channel to perform a SmartCal.

3. Cal All tells Ch 3 to perform its own SmartCal.

4. When the calibration is done:

1. Channel 200 SmartCal computes error terms, and passes them to Ch1 and Ch2.

2. Ch 3 computes its own error terms (since it performed its own SmartCal).

Split Cal and Independent Calibration Channels Setup

1. Start the Cal All Wizard.
2. In the Measurement Class Cal Properties dialog, enable Split Cal by selecting True from the drop-down menu:
   
   
   
3. Select the channels for Independent Calibration Channels as shown below:
   
   
   
4. For any channels that are 1) Split Cal (SMC/GCX), 2) Cal Receiver Port Only at Low Frequency (banded noise only), or 3) Independent Calibration Channels, note the following:

1. These channels will be performing their own SmartCal calibrations and will NOT inherit a calest from the Cal All calibration.

2. Connection lists will be organized such that even if several channels are performing the same connection as part of their calibration the user will be prompted only once. For example, if channels 2, 3, and 200 (CalAll channel) will be needing a power sensor on port one, then the user will be prompted once for this connection, and channels 2,3, and 200 will take power sweeps consecutively.

3. Settings made from the GUI apply to all active calibrations. If a user wants to set different calibration settings, use the remote UI (with the appropriate channel number). The only exception is that the user may choose specific calibration powers (if allowed) for each channel performing its own Calibration. This is accomplished using the SENSe:CORRection:COLLect:GUIDed:PSENsor:POWer:LEVel SCPI command and the PowerCalibrationPowerLevel COM command.  From the GUI, this is accomplished in the following Power Cal Page:
   
   

Note: Some channels do not support setting the cal power level. If this is the case, then the field will be disabled.

5. On the last Cal All Wizard page, the Description column specifies whether the channel is being calibrated by Cal All or performing its own calibration: If it is being calibrated by Cal All, it displays which Cal All channel is performing the calibration.
   
   (Scrolled to the left)
   
   
   (Scrolled to the right)
   

Note: If a user chooses to Enable Extra Power Cals, then the only client channels that are participating in Cal All as normal will inherit the corresponding power calibration terms (this is most often used with SA, which cannot be an Independent Calibration Channel).

Calibration Attenuator Settings dialog box help

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 analyzer 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

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 analyzer 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 channels 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.

Noise Reduction

This button accesses the following dialog for settings that help reduce trace noise and the noise floor which can lead to better dynamic range and more accurate measurements. Learn more.

IF Bandwidth

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.

Always ON

Check to enable averaging.

Average Factor

Specifies the number of measurements that are averaged. Range of 1 to 65536 (2^16).

Average Type

Sweep  Each data point is based on the average of the same data point measured over consecutive sweeps.

(Sweep) Restart   Begins a new set of measurements that are used for the average. Applies only to Sweep averaging - NOT Point.

Point   Each data point is measured the number of times specified by the Average Factor, and then averaged, before going to the next data point.

Reduce IF BW at Low Frequencies

When this box is checked, the VNA uses a smaller IF Bandwidth than the selected value. Learn more.

Select DUT Connectors and Cal Kits dialog box help

For each DUT port:

• Select the connector at the calibration reference plane (where the cal standards will be connected).

• Select the cal kit to be used.

Check Modify Cal to change the Thru method. An Unknown Thru cal is performed by default. Learn about THRU methods.

Learn more about this dialog.

Power Cal Settings dialog box help

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.

• To use the same power sensor for all power cals, do NOT check Use Multiple Sensors.

• To use different power sensors, check Use Multiple Sensors. The sensor must be configured as a PMAR device. Learn how.

Learn about this dialog box.

Cal All Summary  dialog box help

This page is a summary of the Cal All settings. Confirm the settings, then click Next > or < Back to change settings.

Cal Steps  dialog box help

Follow the prompts to connect each standard. Then click Measure.

Click Re-measure if necessary.

Then click Next >

Finish Cal  dialog box help

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.

Learn more about this dialog.