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Using a Bonded Configuration

This capability requires Option CB4/CB5 and N7653APPC.

When in bonded configuration, a waveform of up to four-times the bandwidth of the channel with the minimum bandwidth can be played. For example, instruments where all channels have CB4 and D20 or D21 (2 GHz bandwidth) can play a waveform up to 8 GHz bandwidth, or instruments where all channels have CB5 and R25 (2.5 GHz bandwidth) can play a waveform up to 10 GHz bandwidth. An external combiner is required to bond the Channel 1 and Channel 2 RF Outputs for two channels bonded and Channel 1 to Channel 4 for four channels bonded configuration to provide a single signal to the Device Under Test.

For the high-fidelity playback of a bonded waveform, a calibration and correction procedure must be performed on a waveform that will play at a given output frequency, power, and instrument temperature. The process requires a supported Keysight X-Series Signal Analyzer (see the list below) and consists of: spectrally splitting a waveform into a set of sub-waveforms (one for each source-channel in the bonded group), aligning the source-channels, and improving the fidelity of each sub-waveform. The alignment process ensures the fidelity of the signal where the frequencies generated by adjacent source-channels overlap. The Using Instrument Nonlinear Correction tutorial is used to initiate the bonding process and improve the fidelity of each sub-waveform.

Supported Receivers for Channel Bonding

The following Keysight products are supported as receivers:

• N9020B

• N9030B

• N9032B

• N9040B

• N9041B

• N9042B

• VSA 89600 running on Signal Analyzer or Oscilloscope

The bonding workflow is as follows:

1. For the M9484C, ensure the Synchronization Alignment has been successfully performed.

   See Perform Alignment.

2. Configure instrument with external combiner and connect the output to the receiver.

3. Configure the channels to create a bonded-group configuration.

   See Select Configuration

4. Set desired frequency and power.

   See Frequency (CW) (Bonded).

   See Power (Total RMS) (Bonded).

5. Select Signal block:

   1. Select a waveform file that is not a *.inc file (a *.bnd file can be selected).

      See File (Bonded).

   2. Set Sample Rate, Occupied Bandwidth, and Scale as appropriate for the waveform. Verify RMS Power is correct.

      See Sample Rate (Bonded).

      See Occupied Bandwidth (Bonded).

      See Scale (Bonded).

      See RMS Power (Bonded).

   3. Configure the markers as appropriate for your test setup.

   4. Set up the bonding process and perform calibration. Note that INC SCPI commands (using the first signal of the bonded group) are used to configure what calibrations/corrections will be utilized during the bonding process.

      See Instrument Nonlinear Correction.

      See Start Calibration.

   5. Set Triggering as appropriate for your test setup.

6. Measure the Device-Under-Test.

As the initial workflow pertains to a specific frequency, power, waveform, and instrument temperature, repeat steps 3 and 4 for any change of the instrument’s settings or temperature drift.

Once a bonded calibration has been successfully performed, a bonded file (same name as the waveform file with a *.bnd extension) is saved in the same folder as the waveform file.

The typical workflow to play a bonded signal when you have a *.bnd file is as follows:

1. For the M9484C, ensure the Synchronization Alignment has been successfully performed.

   See Perform Alignment.

2. Configure instrument with external combiner.

3. Configure the channels to create a bonded configuration.

   See Select Configuration

4. Select Signal Block:

   1. Select File and select a *.bnd file.

      See File (Bonded).

   2. Restore the bonded State.

      See Recall Calibrated State (Bonded).

   3. Enable Vector Modulation.

   4. Turn RF On.

   5. Set Triggering as appropriate for your test setup.

5. Measure the Device-Under-Test.

The typical workflow to re-calibrate or re-bond a *.bnd file:

1. For the M9484C, ensure the Synchronization Alignment has been successfully performed.

   See Perform Alignment.

2. Configure the channels to create a bonded-group configuration.

   See Select Configuration

3. Set desired frequency and power.

   See Frequency (CW) (Bonded).

   See Power (Total RMS) (Bonded).

4. Select Signal block:

   1. Select a waveform file that is not a *.inc file (a *.bnd file can be selected).

      See File (Bonded).

   2. Set Sample Rate, Occupied Bandwidth, and Scale as appropriate for the waveform. Verify RMS Power is correct.

      See Sample Rate (Bonded).

      See Occupied Bandwidth (Bonded).

      See Scale (Bonded).

      See RMS Power (Bonded).

   3. Configure the markers as appropriate for your test setup.

   4. Set up the bonding process and perform calibration:

      The calibrations to be performed can be changed as desired and select Start Calibration to perform a new calibration. After the bonding process completes, the contents of the existing *.bnd file will be overwritten and the resulting waveform will be playing.

      See Start Calibration.

      Alternatively, select Re-bond to only re-align the channels. After the bonding process completes, the channel bonding data and waveform data will be updated in the .bnd file. The waveform will be playing using new bonding data.

      See Re-bonding.

5. Measure the Device-Under-Test.

As a *.bnd file pertains to a specific Frequency, Power, Waveform, and instrument temperature, you may want to rename the *.bnd file to reflect the test conditions.

The power and frequency can be modified after the bonding process. However, the fidelity of the generated signal will likely degrade. You will need to verify the fidelity of a bonded signal after changing power or frequency. If playback of a bonded signal at different frequencies or power levels is required, then multiple *.bnd files can be generated (rename the *.bnd file at the completion of the bonding process to avoid it being overwritten).

The following table covers the nominal modulation bandwidth limits for hardware options and frequency (given both channels must have the same options).

Table: Vector Modulation BW for Channel Bonding

If a configuration of instrument settings exceeds the available bandwidth a warning message is provided:

Modulation BW is greater than instrument’s BW (<bandwidth>) at this frequency

In such situations you may operate the instrument with resulting performance, or reduce the modulation bandwidth to resume operation within the available bandwidth.

Apply Bonded Correction

Remote command only.

This action applies a correction from the specified .bnd file to a currently selected uncorrected waveform. The result is a new .bnd file with the same base name as that of the currently selected waveform. The new file will contain both data generated as part of the correction process as well as data from the original file.

The correction process applies the memory model polynomial generated during the calibration process to the uncorrected waveform. The fundamental requirement is that the memory model must be applicable to the waveform being corrected.

The following SCPI command applies either an INC or bonded correction:

• For an INC correction, an independent group must be utilized (and only a .inc file can be used in this case),

• For a bonded correction, a channel bonded group must be utilized (and only a .bnd file can be used in this case).

Bonded Configuration SCPI  Example

The following SCPI sequence configures a bonded calibration using only the distortion calibration with no compaction, then performs the calibration, and determines the completion status. In this example, the ACP and power calibrations are disabled, as well as turning off compaction, for illustrative purposes only.

Notes:

1. If a WFM file is utilized, some of the waveform properties may automatically be configured; however, it’s recommended to verify the waveform properties that the bonding calibration will utilize.

2. The following example takes advantage of the default calculated values for many of the bonding calibration settings.

Related Topics

Configure Channel Bonding (user interface and SCPI descriptions)

Channel Bonding Temperature Compensation Using SCPI

Instrument Nonlinear Correction (INC) (user interface and SCPI descriptions)

Using Instrument Nonlinear Correction (INC) (Tutorial)