Time and Frequency Domain Analysis

System responses such as Bode plots and step responses; system characteristics such as response time and overshoot; simulation

Time-domain and frequency-domain analysis commands let you compute and visualize SISO and MIMO system responses such as Bode plots, Nichols plots, step responses, and impulse responses. You can also extract system characteristics such as rise time and settling time, overshoot, and stability margins. Most linear analysis commands can either return response data or generate response plots. To get started with plotting commands, see Plotting System Responses. To create plots whose properties are customizable at the command line, see Plot Customization.

App

Linear System Analyzer

Analyze time and frequency responses of linear time-invariant (LTI) systems

函数

全部展开

Time-Domain Analysis

`step`	Step response plot of dynamic system; step response data
`stepinfo`	Rise time, settling time, and other step-response characteristics
`impulse`	Impulse response plot of dynamic system; impulse response data
`initial`	System response to initial states of state-space model
`lsim`	Plot simulated time response of dynamic system to arbitrary inputs; simulated response data
`lsiminfo`	Compute linear response characteristics
`gensig`	Create periodic signals for simulating system response with `lsim`
`covar`	Output and state covariance of system driven by white noise
`RespConfig`	Options for step or impulse responses

Frequency-Domain Analysis

`bode`	Bode plot of frequency response, or magnitude and phase data
`bodemag`	Magnitude-only Bode plot of frequency response
`nyquist`	Nyquist plot of frequency response
`nichols`	Nichols chart of frequency response
`ngrid`	Superimpose Nichols chart on Nichols plot
`sigma`	Singular value plot of dynamic system
`freqresp`	Evaluate system response over a grid of frequencies
`evalfr`	Evaluate system response at specific frequency
`dcgain`	Low-frequency (DC) gain of LTI system
`bandwidth`	Frequency response bandwidth
`getPeakGain`	Peak gain of dynamic system frequency response
`getGainCrossover`	Crossover frequencies for specified gain
`fnorm`	Pointwise peak gain of FRD model
`norm`	Norm of linear model
`db2mag`	Convert decibels (dB) to magnitude
`mag2db`	Convert magnitude to decibels (dB)

实时编辑器任务

Create Plot

Interactively create linear analysis response plots in the Live Editor

模块

LTI System	Use linear time invariant system model object in Simulink
LPV System	Simulate Linear Parameter-Varying (LPV) systems

主题

Analysis Plots Basics

Plotting System Responses
This example shows an overview of generating time-domain and frequency-domain response plots.

Time-Domain Analysis

Time-Domain Responses

Generate and visualize time-response data such as step response and impulse response.
Time-Domain Characteristics on Response Plots
Visualize time-domain system characteristics such as settling time and overshoot on response plots.
Numeric Values of Time-Domain System Characteristics
Use the stepinfo function to obtain numeric values of step response characteristics such as rise time, settling time, and overshoot.
Response from Initial Conditions
Compute and plot the response of a state-space (ss) model to specified initial state values.
仿真具有任意输入和初始条件的模型
使用线性仿真工具仿真系统对任意输入信号和初始条件的响应。
Import LTI Model Objects into Simulink
Use the LTI System block to import linear system model objects into Simulink^®.

Frequency-Domain Analysis

Frequency-Domain Responses

Generate and visualize frequency-response data such as Bode plots and Nichols plots.
- Frequency Response of a SISO System
- Frequency Response of a MIMO System
Frequency-Domain Characteristics on Response Plots
Visualize frequency-domain system characteristics such as peak response on plots.
Numeric Values of Frequency-Domain Characteristics of SISO Model
Obtain numeric values of frequency-domain characteristics such as peak gain, dc gain, and system bandwidth.

Linear System Analyzer

Joint Time-Domain and Frequency-Domain Analysis
Compare multiple types of responses side by side, including both time-domain and frequency-domain responses, using the Linear System Analyzer app.
使用线性系统分析器进行线性分析
使用线性系统分析器分析一个或多个线性模型的时域和频域响应。
Analyzing MIMO Models
In analysis plots of multiple-input, multiple output LTI models, there are plot tools for selecting subsystems and grouping I/O pairs.

Systems with Time Delays

Analysis of Systems with Time Delays
The time and frequency responses of delay systems can have features that can look odd to those only familiar with delay-free LTI analysis.
Analyzing Control Systems with Delays
Many processes involve dead times, also referred to as transport delays or time lags. Controlling such processes is challenging because delays cause phase shifts that limit the control bandwidth and affect closed-loop stability.