realizemdl

Simulink subsystem block for filter

Syntax

realizemdl(hq)
realizemdl(hq,Name,Value)


Description

realizemdl(hq) generates a model of filter hq in a Simulink^® subsystem block using sum, gain, and delay blocks from Simulink. The properties and values of hq define the resulting subsystem block parameters.

realizemdl requires Simulink. To accurately realize models of quantized filters, use Fixed-Point Designer™.

realizemdl(hq,Name,Value) generates the model for hq with additional options specified by one or more Name,Value pair arguments. Using name-value pair arguments lets you control more fully the way the block subsystem model gets built. You can specify such details as where the block goes, what the name is, or how to optimize the block structure.

Input Arguments

hq — Filter System object™

filter System object

List of filter system objects that the function supports:

Filter System objects
dsp.AllpassFilter
dsp.AllpoleFilter
dsp.BiquadFilter
dsp.CICCompensationDecimator
dsp.CICCompensationInterpolator
dsp.CoupledAllpassFilter
dsp.FarrowRateConverter
dsp.FilterCascade
dsp.FIRFilter
dsp.FIRInterpolator
dsp.FIRDecimator
dsp.FIRRateConverter
dsp.FIRHalfbandDecimator
dsp.FIRHalfbandInterpolator
dsp.HighpassFilter
dsp.IIRFilter
dsp.IIRHalfbandDecimator
dsp.IIRHalfbandInterpolator
dsp.LowpassFilter
dsp.NotchPeakFilter

Name-Value Pair Arguments

'Destination' — Destination choices:

'current' (default) | 'new' | subsystemname

Specify whether to add the block to your current Simulink model or create a new model to contain the block. If you provide the name of a current subsystem in subsystemname, realizemdl adds the new block to the specified subsystem.

'Blockname' — The name of the block (not the default) :

'filter' (default)

Provide the name for the new subsystem block. By default the block is named Filter.

'MapCoeffstoPorts' — Value options:

'off' (default) | 'on'

Specify whether to map the coefficients of the filter to the ports of the block.

'MapStates' — Value options:

'off' (default) | 'on'

Specify whether to apply the current filter states to the realized model. Such specification allows you to save states from a filter object you may have used or configured in a specific way. The default setting of 'off' means the states are not transferred to the model. Setting the property to 'on' preserves the current filter states in the realized model.

'OverwriteBlock' — Value options:

'off' (default) | 'on'

Specify whether to overwrite an existing block with the same name or create a new block.

'OptimizeZeros' — Value options:

'off' (default) | 'on'

Specify whether to remove zero-gain blocks.

'OptimizeOnes' — Value options:

'off' (default) | 'on'

Specify whether to replace unity-gain blocks with direct connections.

'OptimizeNegOnes' — Value options:

'off' (default) | 'on'

Specify whether to replace negative unity-gain blocks with a sign change at the nearest sum block.

'OptimizeDelayChains' — Value options:

'off' (default) | 'on'

Specify whether to replace delay chains made up of n unit delays with a single delay by n.

'CoeffNames' — Names of coefficients:

{'Num'} (default FIR) | {'Num','Den'} (default direct form IIR) | {'Num','Den','g'} (default IIR SOS) | {'Num_1,'Num_2,'Num_3'...} (default multistage) | {'K'} (default form lattice)

Specify the coefficient variable name as a cell array of character vectors. MapCoeffsToPorts must be set to 'on' for this property to apply.

'InputProcessing' — Possible input processing options:

'columns as channels' (default) | 'elements as channels'

Specify sample-based ('elements as channels') or frame-based ('columns as channels') processing.

'RateOption' — Rate options:

'enforce single rate' (default) | 'allow multirate'

Specify how the block adjusts the rate at the output to accommodate the reduced number of samples. This parameter applies only when InputProcessing is 'columns as channels'.

'Arithmetic' — Value types:

'double' | 'single'

The arithmetic for System object inputs must be 'double' or 'single'.

Limitations

The destination must be a Simulink model. The function does not support a library file destination.

Examples

Realize Simulink Model of a Lowpass Butterworth Filter

d = fdesign.lowpass('N,F3dB',4,0.25);
filterobject = design(d,'butter','systemobject',true);

Create a new model, LPFilter.slx, and realize the subsystem block in this model.

new_system('LPFilter');
realizemdl(filterobject);

View the block diagram by clicking on the subsystem block.

Create a new model, LPFilterMapping.slx, and realize the subsystem block, with coefficients mapped to ports, in this model.

new_system('LPFilterMapping');
realizemdl(filterobject,'MapCoeffsToPorts','on');

View the block diagram by clicking on the subsystem block.

In this case, the filter is an IIR filter with a direct form II second-order sections structure. Setting MapCoeffstoPorts to 'on' exports the numerator coefficients, the denominator coefficients, and the gains to the MATLAB® workspace using the default variable names Num, Den, and g. Each column of Num and Den represents one second-order section. You can modify the filter coefficients directly in the MATLAB workspace providing tunability to the realized Simulink model.