You are reading the article **How To Compute The Cross** updated in October 2023 on the website Vibergotobrazil.com. We hope that the information we have shared is helpful to you. If you find the content interesting and meaningful, please share it with your friends and continue to follow and support us for the latest updates. *Suggested November 2023 How To Compute The Cross*

MATLAB’s xcorr method can be used to compute the cross-correlation of 2 time-sequences which are discrete in nature. The main aim of computing cross-correlation is to enable the use of a part of any incoming signal or beam to examine the transient evolution that is being produced by the second part. It can also be used to get the additional information of the incoming signal or beam itself which is otherwise tricky to measure.

Start Your Free Data Science Course

Hadoop, Data Science, Statistics & others

Syntax:

C = xcorr (a, b) is used to return the cross-correlation between two time sequences (discrete in nature).

The method ‘xcorr’ will compute the similarity between vector ‘a’ & lagged copies of vector ‘b’

Let us now understand how to compute the cross-correlation in MATLAB using ‘xcorr’ method:

Examples of Matlab xcorrLet us discuss examples of Matlab xcorr.

Example #1In this example, we will use the xcorr method to compute the cross-correlation between 2 vectors. The steps to be followed for this example are:

Create a vector ‘a’

Create another vector ‘b’, with a shift of required units from ‘a’

Pass the above 2 vectors as arguments to the xcorr method

Use the stem method to plot the output

Code:

x = 0 : 20

[Initializing the size of the vector]

[Initializing the vector ‘a’]

b = circshift(a, 10);

[Initializing the vector ‘b’. Here we have used ‘circshift’ method to get a vector which is shifted by 10 elements from ‘a’]

[c, lag] = xcorr(a, b);

[Using the xcorr method to get the cross correlation]

stem(lag, c)

[Using stem method to plot the output]

This is how our input and output will look like in Matlab command window:

Input:

Output:

As we can see in the OUTPUT, largest spike comes at -10; i.e. when the elements of a & b match exactly, which is the same as expected by us.

Example #2Let us take another example where we will use xcorr method to compute the cross-correlation between 2 vectors. The steps to be followed for this example are:

Create a vector ‘a’

Create another vector ‘b’, with a shift of required units from ‘a’

Pass the above 2 vectors as arguments to the xcorr method

Use the stem method to plot the output

Code:

x = 0 : 40

[Initializing the size of the vector]

a = 0.48.^x;

[Initializing the vector ‘a’]

b = circshift(a, 8);

[Initializing the vector ‘b’. Here we have used ‘circshift’ method to get a vector which is shifted by 8 elements from ‘a’]

[c, lag] = xcorr(a, b);

[Using the xcorr method to get the cross correlation]

stem(lag, c)

[Using stem method to plot the output]

This is how our input and output will look like in Matlab command window:

Input:

As we can see in the OUTPUT, largest spike comes at -8; i.e. when the elements of a & b match exactly, which is the same as expected by us.

In the above 2 examples there was no limit on the lag. Next, we will learn how to define a lag in the xcorr method

Example #3In this example, we will use xcorr method to compute the cross-correlation between 2 vectors and will limit the maximum lag. The steps to be followed for this example are:

Create a vector ‘a’

Create another vector ‘b’, with a shift of required units from ‘a’

Pass the above 2 vectors as arguments to the xcorr method

In addition to the above 2 arguments, pass a 3rd argument which will specify the maximum lag

Use the stem method to plot the output

Code:

x = 0 : 50

[Initializing the size of the vector]

a = 0.90.^x;

[Initializing the vector ‘a’]

b = circshift(a, 5);

[Initializing the vector ‘b’. Here we have used ‘circshift’ method to get a vector which is shifted by 5 elements from ‘a’]

[c, lag] = xcorr(a, b, 15);

[Using the xcorr method to get the cross correlation. Please note that, we have passed a 3rd argument ‘15’, which represents the maximum lag that we need]

stem(lag, c)

[Using stem method to plot the output]

This is how our input and output will look like in Matlab command window:

Input:

Output:

Example #4Let us take another example where we will use xcorr method to compute the cross-correlation between 2 vectors and will limit the maximum lag. The steps to be followed for this example are:

Create a vector ‘a’

Create another vector ‘b’, with a shift of required units from ‘a’

Pass the above 2 vectors as arguments to the xcorr method

Pass a 3rd argument which will specify the maximum lag

Use the stem method to plot the output

Code:

x = 0 : 100

[Initializing the size of the vector]

a = 0.200.^x;

[Initializing the vector ‘a’]

b = circshift(a, 10);

[Initializing the vector ‘b’. Here we have used ‘circshift’ method to get a vector which is shifted by 10 elements from ‘a’]

[c, lag] = xcorr(a, b, 20);

[Using the xcorr method to get the cross correlation. Please note that, we have passed a 3rd argument ‘20’, which represents the maximum lag that we need]

stem(lag, c)

[Using stem method to plot the output]

This is how our input and output will look like in Matlab command window:

Input:

Output:

As we can see in the output, the signal is restricted with a maximum lag of 20 as expected by us

ConclusionThe xcorr method can be used in MATLAB to compute the cross-correlation of 2 time-sequences which are discrete in nature. If required, we can limit the maximum lag as per our requirement.

Recommended ArticlesThis is a guide to Matlab xcorr. Here we discuss the Introduction, How to compute the cross-correlation in Matlab along with the examples for better understanding. You may also have a look at the following articles to learn more –

You're reading __How To Compute The Cross__

Update the detailed information about **How To Compute The Cross** on the Vibergotobrazil.com website. We hope the article's content will meet your needs, and we will regularly update the information to provide you with the fastest and most accurate information. Have a great day!