I/Q Imbalance Compensator
Compensate for imbalance between in-phase and quadrature components
RF Impairments Correction
The I/Q Imbalance Compensator mitigates the effects of an amplitude and phase imbalance between the in-phase and quadrature components of a modulated signal. The supported modulation schemes include OFDM, M-PSK, and M-QAM, where M > 2.
This block accepts up to three input ports, of which one is
the input signal. When you set the Source of compensator
coefficient parameter to
Estimated from input
signal, two additional input ports are enabled. The
first is enabled when you set the Source of adaptation step
size parameter to
Input port and
the second is enabled when you check the Coefficient adaptation
input port box. The two options are independent. Additionally,
you can check the Estimated coefficient output port box
to create an optional output port from which the estimated compensator
coefficients are made available.
When you set the Source of compensator coefficient parameter
Input port, only one possible configuration
is possible (input signal port, coefficient input port, and output
- Source of compensator coefficient
Specify the source of the compensator coefficients as
Estimated from input signalor
Input port. If set to
Estimated from input signal, the compensator calculates the coefficients from the input signal. If set to
Input port, all other properties are disabled and you must provide the coefficients through the input port. The default value is
Estimated from input signal.
- Initial compensator coefficient
Specify the initial coefficient used by the internal algorithm to compensate for the I/Q imbalance. The default value is
- Source of adaptation step size
Specify the source of the adaptation step size as
Input port. If set to
Property, specify the step size in the Adaptation step size field. If set to
Input port, you must specify the step size through an input port. The default value is
- Adaptation step size
Specify the step size of the adaptation algorithm as a real scalar. This parameter is available only when Source of adaptation step size is set to
Property. The default value is
- Coefficient adaptation input port
Select this check box to create an input port that permits a signal to control the adaptation process. If the check box is selected and if the input signal is
true, the estimated compensation coefficients are updated. If the adaptation port is not enabled or if the input signal is
false, the compensation coefficients do not change. By default, the check box is not selected.
- Estimated coefficient output port
Select this check box to provide the estimated compensation coefficients to an output port. By default, the check box is not selected.
This block implements the algorithm, inputs, and outputs described
comm.IQImbalanceCompensator reference page. The object properties correspond
to the block parameters.
Supported Data Types
|Port||Supported Data Types|
 Anttila, L., M. Valkama and M. Renfors. "Blind Compensation of Frequency-Selective I/Q Imbalances in Quadrature Radio Receivers: Circularity-Based Approach." Proc. IEEE ICASSP. 2007, pp. III-245 -III-248.
 Kiayani, A., L. Anttila, Y. Zou, and M. Valkama, "Advanced Receiver Design for Mitigating Multiple RF Impairments in OFDM Systems: Algorithms and RF Measurements." Journal of Electrical and Computer Engineering. Vol. 2012.
Introduced in R2014b