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Correction Settings...

The MXG and EXG Internal Arbs come equipped with an internal calibration which is comparable to the N7620B corrections. This means that if the MXG or EXG calibration is enabled the Pulse Building corrections are not needed. Enable the MXG/EXG internal calibrations by checking Enable Predistortion on The Arb tab of the Customize… panel.

This menu item displays the ClosedCorrection Settings dialog. Select the type of corrections to use for the signal.

The Correction Settings... dialog enables and disables corrections. When enabled, corrections are applied to downloaded waveforms and are based on certain system parameters, including:

  • Hardware configuration

  • Mirror spectrum

  • Signal generator model

  • Modulator attenuator value

  • Signal generator serial number

  • Baseband filter

  • Arbitrary waveform generator model

  • Arb Sample clock frequency

  • Frequency

  • Arb output voltage

  • Frequency offset

  • Arb output filter

  • Amplitude

  • Number of calibration points

  • Amplitude offset

  • Signal bandwidth

  • Attenuator value

 

These parameters are used as a key into the calibration data base kept in the Signal Generator. If an entry exist the corrections are applied to the waveform. If no entry matches the key, a new calibration measurement is made using the ESA/PSA spectrum analyzer. This measurement data is added to the calibration data file and used to correct the waveform as it is downloaded.

Click Closedhere to view the signal download flow diagram.

The Pulse Building application provides direct access for calibration. Ensure that the signal generator, the arbitrary waveform generator and spectrum analyzer share a common 10 MHz reference and are connected correctly. Run the system Self Test if you are unsure of the system configuration. The PSG/MXG/EXG/ESG signal generator has an automatic sensing 10 MHz reference input. The ESA/PSA spectrum analyzer is not auto sensing and must be configured to accept an external reference or to output a 10 MHz reference. External arbitrary waveform generators are always configured for an external 10 MHz reference and the PSG/MXG/EXG/ESG internal Arb shares the same reference used by the signal generator (see Equipment Setup).

Auto-Correction

When this check box is enabled, the Pulse Building application's automatic correction routine is used. This routine corrects for RF flatness and image rejection. When Auto-Correction is enabled, both Image Rejection and RF Modulation Flatness and Phase are selected.

For best performance, an I/Q Calibration from the signal generator's front panel is recommended on a regular basis. The I/Q calibration should be done about once a week.

See also System Optimization.

Optimization

The correction measurement can be optimized for accuracy or speed. Optimizing for speed means that fewer measurement points are made. A waveform pre-distorted with fewer data points may provide less correction to the linear distortions in the hardware. Custom optimization lets you specify how many measurements are made across the bandwidth for each correction. The actual number of measurements made for Accuracy and Speed are configuration specific.

 

Speed

Accuracy

Custom

Internal I/Q

25

100

25-1000

External I/Q

25

100

25-1000

Wideband I/Q

50

200

25-1000

Disable Spectrum Analyzer Display

This feature allows the spectrum analyzer display to be blanked during the correction measurement. It can be used to hide operational frequencies from general view.