www.gusucode.com > ident 案例代码 matlab源码程序 > ident/AnalyzeTimeSeriesModelExample.m
%% Analyze Time-Series Models % This example shows how to analyze time-series models. %% % A time-series model has no inputs. However, you can use many response % computation commands on such models. The software treats (implicitly) the % noise source |e(t)| as a measured input. Thus, % |step(sys)| plots the step response assuming that the % step input was applied to the noise channel |e(t)|. %% % To avoid ambiguity in how the software treats a time-series model, you % can transform it explicitly into an input-output model using |noise2meas|. % This command causes the noise input |e(t)| to be treated as a measured % input and transforms the linear time series model with |Ny| outputs into an % input-output model with |Ny| outputs and |Ny| inputs. You can use the % resulting model with commands, such as, |bode|, |nyquist|, and |iopzmap| to % study the characteristics of the |H| transfer function. %% % Estimate a time-series model. load iddata9 sys = ar(z9,4); %% % Convert the time-series model to an input-output model. iosys = noise2meas(sys); %% % Plot the step response of |H|. step(iosys); %% % Plot the poles and zeros of |H|. iopzmap(iosys); %% % Calculate and plot the time-series spectrum directly without converting % to an input-output model. spectrum(sys); %% % The command plots the time-series spectrum amplitude $\Phi (\omega ) = % {\left\| {H(\omega )} \right\|^2}$. %