iTMSA (Integrated True Mode Stimulus Application)

Important Note

When the first iTMSA measurement is created, an IFMUX Cal is performed, which takes a couple of minutes.

When finished, Exit then restart the PNA App.

If an IF board is replaced, this Cal should be performed again. To make this happen, delete c:\users\public\network analyzer\IFMUX.txt. When the next iTMSA measurement is created, the file will be recreated with new data.

How to create an iTMSA trace:

1. Preset the PNA

2. Then do the following:

Using front-panel
hardkey [softkey] buttons

Using Menus

1. Press Meas

2. then [Balanced Parameters]

3. then press the Change button

1. click Response

2. then Measure

3. then Balanced Parameters

4. then press the Change button

Balanced DUT Topology / Logical Port Mapping (with iTMSA Option 460 ) dialog box

Learn about iTMSA.

Topology

Only the following topologies and port mappings are available in True Mode Stimulus:

• BAL  DUT has a single balanced port. The VNA ports are restricted to the following:

• Balanced Port 1 = VNA ports 1 and 3

• BAL-BAL  DUT has two balanced ports. The VNA ports are restricted to the following:

• • Balanced Port 1 = VNA ports 1 and 3

  • Balanced Port 2 = VNA ports 2 and 4

• BAL-SE   DUT has one balanced port and one single-ended port. The VNA ports are restricted to the following:

• Balanced Port 1 = VNA ports 1 and 3.

• Single-ended Port 2 = VNA port 2.

• SE- BAL   DUT has one single-ended port and one balanced port. The VNA ports are restricted to the following:

• Single-ended Port 1 = VNA port 1.

• Balanced Port 2 = VNA ports 2 and 4.

• Custom  Maps the physical VNA ports to a device of balanced and single-ended logical ports for multi-port systems with greater than 4 ports.

Stimulus

Single Ended  Standard PNA mode. Each DUT port receives stimulus individually.

True Mode  Each balanced port receives true balanced stimulus in both forward and reverse directions.

Forward True Mode  Available ONLY in BAL- BAL topology. Only Balanced port 1 receives true balanced stimulus.

Reverse True Mode  Available ONLY in SE- BAL topology. Only Balanced port 2 receives true balanced stimulus.

Source ONLY Mode  Creates a true, differential CW frequency source. Can NOT be used to make measurements of the DUT. If the sweep type is set to linear frequency, the first point is the CW frequency.

Balanced Port Offset

Select Port  Select the physical PNA port to receive a phase or power offset. Only port 3 and port 4 are available for Phase or Power offset.

Phase Offset  Specify offset within +/- 180° for the balanced INPUT port. This is in addition to the standard offsets, which are 180° offset for the differential stimulus sweeps, and 0° for the common stimulus sweeps.

Offset (phase) as Fixture

When unchecked, output calculations are performed and displayed as though there is only the standard offset. Although additional Phase Offset is applied to the stimulus, it is ignored in the calculations of balanced differential and common mode output signals.

When checked, output calculations are performed and displayed using the actual phase offset that is applied to the DUT. Use this setting to compensate for a component or fixture that may present a phase delay before the DUT.

Power Offset  Specify power offset. Range is  +/- 2 dB. This is in addition to the power level that is specified using the Power and Attenuators dialog. Offset Power is NOT reflected on the power dialog nor on the X-Axis during a power sweep.

Offset (power) as Fixture

When unchecked, output calculations are performed and displayed as though there is no stimulus power offset.

When checked, output calculations are performed and displayed using the power offset that is applied to the DUT. Use this setting to compensate for a component or fixture that may present a magnitude loss before the DUT.

Phase Sweep

• Available only when Sweep type = CW.

• Only PNA port 3 OR port 4 are eligible for Phase sweep.

• Available ONLY for balanced pairs.

The phase of the selected port (3 or 4) is swept relative to the phase of the other port (1 or 2) in the balanced pair.

Phase Sweep is similar to phase offset, except that for each data point, the phase 'offset' is incremented.

For example, with the topology that is selected in the above image: (Bal-Bal) Logical port 1 = PNA ports 1 and 3. For a phase sweep with 7 data points, from 0° to 180°, the phase difference between port 1 and port 3 increments 30° with each data point:

Enable Phase Sweep  Check to enable phase sweep for the specified port.

Sweep Phase  Choose EITHER PNA Port 3 OR Port 4 to sweep.  Only ONE port can be phase swept.

Start / Stop Phase  Enter phase values in degrees.  Each sweep will start and stop at these settings.

Offset (phase) as Fixture

In the following image, the PNA phase sweep is shown as a phase shifter that is "virtually" located EITHER before the reference receiver (top) OR after the reference receiver (bottom) - NOT BOTH.  This image is useful as a model ONLY.

One use for Phase Sweep

Do the following to find best the best operating point:

1. Phase sweep port 3, from 0° to 180°.  Note the peak of Sdd21.  This finds the phase offset of the input differential port.  

2. Set port 3 fixed offset to the phase that has the highest Sdd21.

3. Then, phase sweep port 4 (balanced port 2) to find the phase offset of the output differential port.

4. Then set the port 4 to fixed phase offset found.  

This measures the best possible case Sdd21 for the DUT.

Power and Attenuation (with True Mode Stimulus) dialog box help  

When a True Mode Stimulus is selected in the Balanced DUT Topology dialog, the balanced ports are shown on the top rows of the dialog. The individual PNA port settings are displayed but can not be changed directly.

Port Powers Coupled  Check to couple all power settings for Balanced Port 1 and Balanced Port 2. Clear this box to make independent power settings for these logical ports.

State  Should be left in Auto for iTMSA measurements. Learn more about his setting.

Port Power  Set power for the balanced port. Power for PNA ports, shown below balanced ports, are set to 3 dB less, or half power. Power Offset is made in addition to this setting, and on only PNA port 3 and port 4. Offset Power is NOT reflected on this dialog nor on the X-Axis.

Start and Stop Power  Available when sweep type is set to power sweep.

Auto Range Check to allow the PNA to select the optimum attenuation value to achieve the specified test port power.  Clear to manually set the attenuation for each port. Type or select the attenuation value in the adjacent Attenuator Control box. When the attenuator setting of a logical port is changed, then the attenuators of the PNA ports associated with that logical port change to the same value.

Leveling Mode  Open Loop leveling is available only on ports 1 and 3.  Learn more.

Note: The range of leveled power (ALC range) for balanced ports is 3 dB higher than it is for each individual PNA port. For example, if a PNA source port with 0 dB attenuation will supply leveled power from -30dBm to +15dBm, then the balanced logical port has a range of -27dBm to +18dBm. Learn more about Leveled Power.

Create / Change Receiver Measurements (with True Mode Stimulus) dialog box help  

Click Activate

• For RATIOED measurements, Select a receiver for the Numerator and select a receiver for the Denominator.

• For UNRATIOED measurements, Select a test port receiver (A, B, C, or D) for the Numerator. Reference receiver measurements are NOT accurate.  Select 1 for the Denominator.

For example, with a Bal-Bal topology, the above selections show a R3/R1 measurement. R (reference) receivers measure the stimulus to the DUT. An R3/ R1 trace shows the difference between the two sources that comprise logical port 1. With Log format, a power offset between the two sources is visible. With Phase format, a phase offset is visible.

Source Port  Specifies whether a Differential stimulus or Common mode stimulus is used for the measurement.

• With Source Port 1 or 2 selected, then Differential stimulus is used for the unratioed measurement which causes 180° offset between the sources.

• • Source Port 1 = Differential stimulus on BAL1 port

  • Source Port 2 = Differential stimulus on BAL2 port

• With Source Port 3 or 4 selected, then Common mode stimulus is used for the unratioed measurement which causes 0° offset between the sources.

• • Source Port 3 = Common-mode stimulus on BAL1 port

  • Source Port 4 = Common-mode stimulus on BAL2 port