Real Time

3. I/Q

I/Q Adjustments

Choice: Off | On

Default: Off

Double-click or use the drop-down menu to turn the I/Q adjustments On or Off.

On – The values entered for I Offset, Q Offset, and so on are applied to the I and Q signals.

Off – I/Q adjustment values are not applied to the I and Q signals.

I Offset

Range: -20% to 20%

Step: 0.025%

Default: 0.000%

Enter a DC offset value to apply to the I signal before the I/Q modulator. Use this offset to remove imperfections in the in-phase signal or to introduce calibrated impairments.

When using this setting to minimize the LO feed-through signal, optimum performance is achieved when the adjustment is made after any other I/Q path adjustments. If other adjustments are made after minimization is performed, the LO feed-through signal may increase.

Set I/Q Adjustments to On to enable this parameter.

Q Offset

Range: -20% to 20%

Step: 0.025%

Default: 0.000%

Enter a DC offset value to apply to the Q signal before the I/Q modulator. Use this offset to remove imperfections in the quadrature-phase signal or to introduce calibrated impairments. When using this setting to minimize the LO feed-through signal, optimum performance is achieved when the adjustment is made after any other I/Q path adjustments. If other adjustments are made after minimization is performed, the LO feed-through signal may increase.

Set I/Q Adjustments to On to enable this parameter.

I/Q Gain Balance

Range: -1 dB to 1 dB in 0.001 dB steps

Default: 0.000 dB

Enter a value to set the gain for the I signal relative to the Q signal.

Example: If you enter a value of 1 dB, the I signal will have 1 dB more amplitude than the Q signal. Use the gain balance to remove imperfections in I and Q or introduce calibrated impairments.

Set I/Q Adjustments to On to enable this parameter.

Quadrature Angle Adjustment

Range: -10 to 10 degrees

Default: 0.00 degrees

Enter a value to adjust the Q phase angle. When the quadrature skew is zero, the phase angle between the I and Q vectors is 90 degrees. Positive skew increases the angle from 90 degrees; negative skew decreases the angle from 90 degrees.

Set I/Q Adjustments to On to enable this parameter.

I/Q Timing Skew Path

Choice: RF | BB (Baseband)

Default: RF

Double-click or use the drop-down menu to select the I/Q timing skew path.

Set I/Q Adjustments to On to enable this parameter.

I/Q Correction Optimization Path

Choice: RF Output | External I/Q Output

Default: RF Output

Double-click or use the drop-down menu to select the I/Q correction optimized path.

RF Output optimizes the RF OUT path by applying calibration factors to only this path, leaving the I/Q OUT and Digital Bus paths uncalibrated.

Ext I/Q Output optimizes the I/Q OUT path by applying calibration factors to only this path, leaving the RF OUT and Digital Bus paths uncalibrated.

I/Q Skew

Range: -500 ns to 500 ns

Default: 0.0 seconds

Enter a value to set the time delay between I and Q.

• A positive value delays the I signal relative to the Q signal.

• A negative value delays the Q signal relative to the I signal.

I/Q Delay

Range: -250 ns to 250 ns

Default: 0.0 seconds

Enter a value to change the absolute phase of both I and Q with respect to triggers and markers. A positive value delays I and Q. This value affects both the external I/Q out signals and the baseband signal modulated on the RF output. This adjustment cannot be used with constant envelope modulation and does not affect external I/Q inputs.

The limits are determined by the rate of the current format.

Related Topics

Instrument