User`s guide

Agilent E6432A Microwave Synthesizer User’s Guide 3-137

Soft Front Panel Help

I/Q Calibration (Option UNG Only)

• The impairments due to the I/Q modulator hardware within the

synthesizer are modeled as I/Q gain imbalance (Ami and Amq),

dc offset (Omi and Omq), and local oscillator deviation from

quadrature (FE).

The modulation signal paths have DAC-controlled gain (I and Q

Gain), offset (I and Q Offset), and quadrature (Quadrature Skew)

adjustments that are used to compensate for impairments. There is

also a DAC-controlled mixer bias voltage (VBLO) which can be

adjusted to maximize mixer dynamic range. Precision voltage

references (V0-V7) are used to generate I and Q pairs (vectors)

during calibration and to produce the Test Tone.

The input to the I/Q modulator can be from the external source

through the front panel connections (I/Q Input Normal) or from the

internal reference sources (I/Q Input Test Tone). Additionally, the

external inputs may be swapped under software control (I/Q Input

Swapped). Having the external inputs swapped inverts the direction

of phase rotation of the I/Q modulator.