Identify all time-varying source blocks in the signal path of any output linearization point marked in the Simulink® model.
Frequency response estimation uses the steady-state response of a Simulink model to a specified input signal. Time-varying source blocks in the signal path prevent the response from reaching steady-state. In addition, when such blocks appear in the signal path, the resulting response is not purely a response to the specified input signal. Thus, time-varying source blocks can interfere with accurate frequency response estimation.
This check finds and reports all the time-varying source blocks which appear in the signal path of any output linearization output points currently marked on the Simulink model. The report:
Includes blocks in subsystems and in referenced models that are in normal simulation mode
Excludes any blocks specified as
frestimateOptions object you enter as the
For more information about the algorithm that identifies time-varying
source blocks, see the
Available with Simulink Control Design™.
Provide the paths of any blocks to exclude from the check. Specify
the block paths as an array of
This array is stored in the
BlocksToHoldConstant field of an option set you
frestimateOptions. See the
frestimateOptions reference page for
Source blocks exist whose output reaches linearization output points currently marked on the model.
Consider holding these source blocks constant during frequency response estimation.
% Get linearization I/Os from the model. mdl = 'scdengine'; io = getlinio(mdl); % Find time-varying source blocks. blks = frest.findSources(mdl,io); % Create options set with blocks to hold constant. opts = frestimateOptions; opts.BlocksToHoldConstant = blks; % Run estimation with the options. in = frest.Sinestream; sysest = frestimate(mdl,io,in,opts);
Sometimes, the model
includes referenced models containing source blocks in the signal
path of an output
linearization point. In such cases, set the referenced models to normal
simulation mode to ensure that this check locates them. Use the
set_param command to set
any referenced models to
Normal before running