User`s guide

3-136 Agilent E6432A Microwave Synthesizer User’s Guide
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I/Q Calibration (Option UNG Only)
The I/Q modulator consists of circuits to select the I/Q input signal
(Normal, Swapped, Test Tone), circuits to select calibration voltages or
a Test Tone, and adjustments for optimizing performance by
minimizing I/Q impairments.
I/Q impairments may be due to the following:
• errors in the gain match between I and Q signal paths
• dc offsets on I and Q signal paths
• deviations from a quadrature phase relationship (90 degrees)
between the I and Q mixer local oscillator signals
These impairments may be due to the external I and Q source
signals being applied and they may be due to the hardware within
the synthesizer itself.
• The external I and Q source signals are modeled as perfect
sources (Si and Sq), followed by impairments in gain (Asi and Asq)
and dc offset (Osi and Osq).