Moving Minimum

Moving minimum

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Libraries:
DSP System Toolbox / Statistics

Description

The Moving Minimum block determines the moving minimum of the input signal along each channel independently over time. The block uses the sliding window method to determine the moving minimum. In this method, a window of specified length moves over each channel sample by sample, and the block determines the minimum over the data in the window. For more details, see Algorithms.

Ports

Input

Port_1 — Data input

column vector | row vector | matrix

Data over which the moving minimum is determined using the sliding window method. The block accepts real-valued or complex-valued multichannel inputs, that is, m-by-n size inputs, where m ≥ 1 and n ≥ 1. The block also accepts variable-size inputs. During simulation, you can change the size of each input channel. However, the number of channels cannot change.

Data Types: single | double
Complex Number Support: Yes

Output

Port_1 — Moving minimum output

column vector | row vector | matrix

Moving minimum output, determined using the sliding window method. The size of the output matches the size of the input. The window slides column-wise along each channel, and the block determines the minimum of the data in the window. For more details, see Algorithms.

Data Types: single | double
Complex Number Support: Yes

Parameters

Specify window length — Flag to specify window length

on (default) | off

When you select this check box, the length of the sliding window is equal to the value you specify through the Window length parameter. When you clear this check box, the length of the sliding window is infinite. In this mode, the block determines the minimum of the current sample and all the previous samples in the channel.

Window length — Length of the sliding window

4 (default) | positive scalar integer

Window length specifies the length of the sliding window in samples.

Dependencies

This parameter appears when you select the Specify window length check box.

Simulate using — Type of simulation to run

Interpreted execution (default) | Code generation

Specify the type of simulation to run. You can set this parameter to:

• Interpreted execution –– Simulate model using the MATLAB^® interpreter. This option shortens startup time.

• Code generation –– Simulate model using generated C code. The first time you run a simulation, Simulink^® generates C code for the block. The C code is reused for subsequent simulations as long as the model does not change. This option requires additional startup time but provides faster subsequent simulations.

Block Characteristics

Data Types	double | integer | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	yes
Zero-Crossing Detection	no

Algorithms

Sliding Window Method

In the sliding window method, the output for each input sample is the minimum of the current sample and the Len - 1 previous samples. Len is the length of the window in samples. When the algorithm computes the first Len - 1 outputs, the length of the window is the length of the data that is available.

When you do not specify the window length, the algorithm chooses an infinite window length. In this mode, the output is the minimum of the current sample and all the previous samples in the channel.

Consider an example of computing the moving minimum of a streaming input data using the sliding window method. The algorithm uses a window length of 4. With each input sample that comes in, the window of length 4 moves along the data.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2016b

R2024a: Change in the default value of Simulate using parameter

The default value of the Simulate using parameter is now Interpreted execution. With this change, the block uses the MATLAB interpreter for simulation by default.