Gain Imb (Custom IQ)

Gain Imb (IQ Gain Imbalance) compares the gain of the I signal with the gain of the Q signal, as follows:

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The effects of IQ gain imbalance are best viewed in constellation diagrams where the width of the constellation diagram is different than its height.

Gain imbalance may be a positive or negative value because it is expressed as a logarithmic value. The gain imbalance is always positive if averaging is ON and Sync Search is OFF.

For non-rectangular formats (such as 8-PSK Phase Shift Keying: A broad classification of modulation techniques where the information to be transmitted is contained in the phase of the carrier wave.), IQ Gain Imbalance may look like Quadrature Skew, and vice-versa. This occurs when the VSA is phase locked to an orientation that is different than that of the modulator.