User`s guide

Agilent E6432A Microwave Synthesizer User’s Guide 3-139
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I/Q Calibration (Option UNG Only)
Vblo Setting
The Vblo Setting is initially set to 2048 and has a range from 0 to 4095.
The Vblo Setting is used to adjust the voltage bias that is applied to the
mixers within the I/Q modulator assembly. Vblo has some affect on the
I/Q modulator conversion loss. Some improvement may be possible, but
the default setting should usually be used. Avoid values below 1000 as
this can cause the mixers to become under biased and distort.
Calibration Settings
The Calibration Settings are the values in the DAC driving the I Gain,
Q Gain, I Offset, Q Offset, and Quadrature (Offset) correction points.
IGain
I Gain is used to enter compensation values for internal gain
impairments in the I signal path. Since it is the ratio of I Gain to
Q Gain that is important, it is usually only necessary to make
adjustments to I Gain or Q Gain, but not both.
QGain
Q Gain is used to enter compensation values for internal gain
impairments for the Q signal path. Since it is the ratio of I Gain to
Q Gain that is important, it is usually only necessary to make
adjustments to I Gain or Q Gain, but not both.
I Offset
I Offset is used to enter an origin offset voltage for the in-phase portion
of an I/Q signal. The value of I Offset is used to adjust out
imperfections in the in-phase signal.
The level of dc offset determines the level of carrier feed-through.
Q Offset
Q Offset is used to enter an origin offset voltage for the
quadrature-phase portion of an I/Q signal. The value of Q Offset is
used to adjust out imperfections in the quadrature-phase signal.