# frest.Sinestream

Input signal containing series of sine waves

## Description

Use a `frest.Sinestream`

object to represent a sinestream input
signal for frequency response estimation. Such a signal consists of sine waves of varying
frequencies applied one after another. Each frequency excites the system for a period of
time.

Sinestream signals are recommended for most situations. They are especially useful when your system contains strong nonlinearities or you require highly accurate frequency response models. The frequency-response model that results when you use a sinestream input contains all the frequencies in the sinestream signal

You can use a sinestream input signal for estimation at the command line, in the Model Linearizer, or with the Frequency Response Estimator block. The estimation algorithm injects the sinestream signal at the input point you specify for estimation, and measures the response at the output point. For more information, see Sinestream Input Signals.

To view a plot of your input signal, type `plot(input)`

. To create a
`timeseries`

object for your input signal, use the `generateTimeseries`

command.

## Creation

You can create a sinestream signal in one of the following ways:

Using the

`frest.Sinestream`

function for continuous-time signalsUsing the

`frest.createFixedTsSinestream`

function for discrete-time signals

For more information, see Sinestream Input Signals.

### Description

creates a signal with a series of sinusoids with properties based on the dynamics of the
linear system `input`

= frest.Sinestream(`sys`

)`sys`

. For instance, if you have an exact linearization
of your system, you can use it to initialize the parameters.

creates a signal with a series of sinusoids with properties
specified using one or more name-value pairs. Enclose each property name in quotes.`input`

= frest.Sinestream(`Name,Value`

)

### Input Arguments

## Properties

## Object Functions

`frestimate` | Frequency response estimation of Simulink models |

`generateTimeseries` | Generate time-domain data for input signal |

`frest.simCompare` | Plot time-domain simulation of nonlinear and linear models |

`frest.simView` | Plot frequency response model in time- and frequency-domain |

`getSimulationTime` | Final time of simulation for frequency response estimation |

## Examples

## Alternative Functionality

### Model Linearizer

In the Model Linearizer, to use a sinestream input signal for estimation, on
the **Estimation** tab, select:

**Input Signal**>**Sinestream**when the sample time of the I/Os is continuous.**Input Signal**>**Fixed Sample Time Sinestream**when the sample time of the I/Os is discrete.

## Version History

**Introduced in R2009b**