Chirp Signal Function

Owning Palette: Signal Generation Functions

Installed With: Control Design and Simulation Module

Generates the point-by-point value of a chirp signal.

Details  Example

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Place on the block diagram

Find on the Functions palette

Dialog Box Options

Parameter	Description
Polymorphic instance	Specifies whether this function is Scalar or Vector. The default value is Scalar.
Parameters	Lists all the parameters associated with this function. Select a parameter from this list to configure the parameter. When you select a parameter, the parameter and its associated Parameter source control appear in the Parameter Information section of the configuration dialog box.
Preview	Displays a graphical preview, if available, of the function output or configuration.
Parameter Information	Contains the parameters you can configure for this function. You must select a parameter from the Parameters list to make that parameter and its associated Parameter source control visible in the Parameter Information section of the configuration dialog box.
Parameter source	Specifies whether you configure this parameter using the Configuration Dialog Box or a Terminal on the simulation diagram. The default value is Configuration Dialog Box. If you select Terminal, LabVIEW displays an input for that parameter on the simulation diagram, and you can wire values to that input to configure this function programmatically. If you select Configuration Dialog Box, LabVIEW removes that input from the simulation diagram. You then must set the value for this parameter inside the configuration dialog box.
target frequency	Specifies the frequency, in hertz, the chirp signal reaches at the target time. The default value is 0.5.
target time	Specifies the simulation time, in seconds, at which the chirp signal reaches the target frequency. After the simulation reaches the target time, the frequency continues to change at the same rate the frequency changed from initial frequency to target frequency. The default value of target time is 10.
initial frequency	Specifies the frequency, in hertz, of the chirp signal at the initial time of the simulation. The default value is 0.01.

Block Diagram Inputs

Parameter	Description
target frequency	Specifies the frequency, in hertz, the chirp signal reaches at the target time. The default value is 0.5.
target time	Specifies the simulation time, in seconds, at which the chirp signal reaches the target frequency. After the simulation reaches the target time, the frequency continues to change at the same rate the frequency changed from initial frequency to target frequency. The default value of target time is 10.
initial frequency	Specifies the frequency, in hertz, of the chirp signal at the initial time of the simulation. The default value is 0.01.

Block Diagram Outputs

Parameter	Description
output	Returns the value of the signal evaluated at the current simulation time. The default value is 1.

Chirp Signal Details

A chirp signal is a sine wave whose frequency varies from initial frequency to target frequency during the simulation time. The current value depends on the current simulation time.

The following equations define the chirp signal.

y = A * sin(2p(f(t)t))

where
	A is the amplitude
	t is the current simulation time
	f0 is the initial frequency
	f1 is the target frequency
	T is the number of time steps between the simulation initial time and the function target time
	y is the output

Feedthrough Behavior

All input/output pairs of this function have direct feedthrough behavior.

Example

Refer to the SimEx Chirp VI in the labview\examples\Control and Simulation\Simulation\Signal Generation directory for an example of using the Chirp Signal VI.

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