I/Q Imbalance
Apply I/Q imbalances to complex signal
Libraries:
Communications Toolbox /
RF Impairments and Components
Description
The I/Q Imbalance block applies inphase and quadrature imbalances to a complex signal. This block applies an amplitude imbalance, a phase imbalance, and a DC offset to the inphase and quadrature signal components. For more information, see I/Q Imbalance Implementation and Algorithms.
Examples
Ports
Input
Output
Parameters
Block Characteristics
Data Types 

Multidimensional Signals 

VariableSize Signals 

More About
Algorithms
The I/Q amplitude imbalance, I/Q phase imbalance, and DC offset impairments are described sequentially in the section.
For an I/Q amplitude imbalance, I_{a}, the impairment is applied to the input signal, x_{r}+ jx_{i} and y _{AmplitudeImbalance} is an intermediate output.
y _{AmplitudeImbalance} $$\triangleq $$ y _{rAmplitudeImbalance} + jy_{iAmplitudeImbalance}
y _{AmplitudeImbalance} = $$\left({10}^{(0.5{I}_{\text{a}}/20)}{x}_{\text{r}}\right)+j\left({10}^{(0.5{I}_{\text{a}}/20)}{x}_{\text{i}}\right)$$
For an I/Q phase imbalance, I_{p}, the impairment is applied to y _{AmplitudeImbalance} and y_{PhaseImbalance} is an intermediate output.
y_{PhaseImbalance} $$\triangleq $$ y_{rPhaseImbalance} + jy_{iPhaseImbalance}
y_{PhaseImbalance} =$$\left({e}^{\left(j\left(0.5\pi {\scriptscriptstyle \frac{{I}_{p}}{180}}\right)\right)}{y}_{{\text{r}}_{\text{AmplitudeImbalance}}}\right)+\left({e}^{\left(j\left({\scriptscriptstyle \frac{\pi}{2}}+0.5\pi {\scriptscriptstyle \frac{{I}_{\text{p}}}{180}}\right)\right)}{y}_{{\text{r}}_{\text{AmplitudeImbalance}}}\right)$$
For DC offsets, I_{DC} and Q_{DC}, the impairment is applied to y _{PhaseImbalance} and y is the final output.
y = (y_{rPhaseImbalance} + I_{DC}) + j(y_{iPhaseImbalance} + Q_{DC})
Variables for these calculations are defined in this list.
I _{a} is the I/Q amplitude imbalance.
I_{p} is the I/Q phase imbalance.
I_{DC} is the inphase DC offset.
Q_{DC} is the quadrature DC offset.
x is the complex input signal and is given by x_{r} + jx_{i}.
x_{r} and x_{i} are the real and imaginary parts, respectively, of x.
y is the complex output signal and is given by y_{r} + jy_{i}.
y_{r} and y_{i} are the real and imaginary parts, respectively, of y.
Extended Capabilities
Version History
Introduced before R2006a
See Also
Blocks
 I/Q Compensator Coefficient to Imbalance  I/Q Imbalance Compensator  Free Space Path Loss  Memoryless Nonlinearity  Phase Noise  Receiver Thermal Noise