Chirp Signal

Generate sine wave with increasing frequency

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Libraries:
Simulink / Sources

Description

The Chirp Signal block generates a sine wave whose frequency increases at a linear rate with time. You can use this block for spectral analysis of nonlinear systems. The block generates a scalar or vector output.

The parameters, Initial frequency, Target time, and Frequency at target time, determine the block's output. You can specify any or all of these variables as scalars or arrays. All the parameters specified as arrays must have the same dimensions. The block expands scalar parameters to have the same dimensions as the array parameters. The block output has the same dimensions as the parameters unless you select the Interpret vector parameters as 1-D check box. If you select this check box and the parameters are row or column vectors, the block outputs a vector (1-D array) signal.

Examples

Track Running Minimum Value of Chirp Signal

This example shows how to track the running minimum value of a signal generated by the Chirp Signal block.

The Chirp Signal block generates a sine wave whose frequency increases at a linear rate with time. The MinMax Running Resettable block tracks the minimum value of that chirp signal over time. The running minimum value is reset every 5 seconds by the Pulse Generator block.

Limitations

• The start time of the simulation must be 0. To confirm this value, go to the Solver pane in the Configuration Parameters dialog box and view the Start time field.

• Suppose that you use a Chirp Signal block in an enabled subsystem. Whenever the subsystem is enabled, the block output matches what would appear if the subsystem were enabled throughout the simulation.

Ports

Output

Port_1 — Chirp signal

scalar | vector | matrix | N-D array

Sine wave whose frequency increases at a linear rate with time. The chirp signal can be a scalar, vector, matrix, or N-D array.

Data Types: double

Parameters

Initial frequency — Initial frequency (Hz)

0.1 (default) | scalar | vector | matrix | N-D array

The initial frequency of the signal, specified as a scalar, vector, matrix, or N-D array.

Programmatic Use

Block Parameter: f1

Type: character vector

Values: scalar | vector | matrix | N-D array

Default: '0.1'

Target time — Target time (seconds)

100 (default) | scalar | vector | matrix | N-D array

Time, in seconds, at which the frequency reaches the Frequency at target time parameter value. You specify the Target time as a scalar, vector, matrix, or N-D array. After the target time is reached, the frequency continues to change at the same rate.

Programmatic Use

Block Parameter: T

Type: character vector

Values: scalar | vector | matrix | N-D array

Default: '100'

Frequency at target time — Frequency (Hz)

1 (default) | scalar | vector | matrix | N-D array

Frequency, in Hz, of the signal at the target time, specified as a scalar, vector, matrix, or N-D array.

Programmatic Use

Block Parameter: f2

Type: character vector

Values: scalar | vector | matrix | N-D array

Default: '1'

Interpret vector parameters as 1-D — Treat vector parameters as 1-D

on (default) | off

When you select this check box, any column or row matrix values you specify for the Initial frequency, Target time, and Frequency at target time parameters result in a vector output whose elements are the elements of the row or column. For more information, see Determine the Output Dimensions of Source Blocks.

Programmatic Use

Block Parameter: VectorParams1D

Type: character vector

Values: 'on' | 'off'

Default: 'on'

Block Characteristics

Data Types	double
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	no
Zero-Crossing Detection	no

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

Not recommended for production code. Relates to resource limits and restrictions on speed and memory often found in embedded systems. Generated code can contain dynamic allocation and freeing of memory, recursion, additional memory overhead, and widely-varying execution times. While the code is functionally valid and generally acceptable in resource-rich environments, smaller embedded targets often cannot support such code. Usually, blocks evolve toward being suitable for production code. Thus, blocks suitable for production code remain suitable.

Version History

Introduced before R2006a