MT Apply IQ Impairments
- Updated2023-02-17
- 4 minute(s) read
MT Apply IQ Impairments
Applies various I/Q impairments to the complex baseband modulated waveform.
Inputs/Outputs
input complex waveform
The modulated complex baseband waveform data.
t0
Trigger (start) time of the Y array.
Default value: 0.0
dt
Time interval between data points in the Y array.
Default value: 1.0
Y
The complex-valued signal-only baseband modulated waveform. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively.
q dc offset
The desired DC offset of the Q waveform as a percentage of the input complex waveform. Valid values are -100 to +100, inclusive.
Default value: 0
iq gain imbalance
The desired ratio of I gain to Q gain, in dB. Valid values are between -6.0 and +6.0.
Default value: 0
quadrature skew
The desired quadrature skew of the complex waveform in degrees. Valid values are between -30.0 and +30.0 degrees.
Default value: 0
error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Default value: No error
i dc offset
The desired DC offset of the I waveform as a percentage of full scale of the input complex waveform. Valid values are between -100 and +100.
Default value: 0.0
impairment definition
A value that indicates which set of equations is used to represent impairments.
In the equations in the following table, is the real component and is the imaginary component of each sample in the input complex waveform. and are the real and imaginary components of the corresponding sample in the output complex waveform. is I DC Offset (%) / 100, and is Q DC Offset (%) / 100.
| Vertical Shear |
The definition uses the following equations for I/Q impairments:
where φ is the specified quadrature skew, in radians = 10(IQ gain imbalance/20)
In matrix form, these equations are represented by
where
|
| Axis Shear |
With this option selected, this node uses an impairment definition that simplifies the conversion between measured impairments and their inverse impairments. For example, you may want to measure the I/Q impairments of a system and compensate for those impairments by applying the inverse impairments to the generated or received waveform. Using the Axis Shear definition, given a measured skew and imbalance (in dB), the inverse impairments are -1.0 * skew and -1.0 * imbalance. This definition uses the following equations for IQ impairments:
where = 10(IQ gain imbalance/20) φ is the specified quadrature skew, in radians In matrix form, these equations are represented by
where
|
Default value: Vertical Shear
frequency offset
The desired frequency offset, in Hertz (Hz), to apply to the output complex waveform.
Default value: 0
reset?
A Boolean that determines whether this node continues applying the impairments using the previous iteration states.
| TRUE | Restarts the impairment generation process. |
| FALSE | Continues applying the impairments using the previous iteration states. |
Default value: TRUE
output complex waveform
The impaired complex baseband modulated waveform data returned by this node.
t0
Trigger (start) time of the Y array.
Default value: 0
dt
Time interval between data values in the Y array.
Default value: 1.0
Y
The complex-valued signal-only baseband modulated waveform. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively.
error out
Error information.
The node produces this output according to standard error behavior.