Sliding a fixed window over an array

Dear Matlab God,

I am in need of help. I want to slide a 80 MHz window through a 1 GHz bandwith array.

Here is an illustation:

As the 80 MHz window sweeps the 1GHz bandwidth, I need find the max and min ponits, subtract them, and store them in an array.

I tiredusing the diff function, but thatonly works for whole number integers.

I think it would be a nested for loop, with a fixed window. Just not sure how to do it.

Thank You,

Ed

Answer 1

[Sourabh Kondapaka]

Hi @Edward Ramirez,

Below is the function which will help in acheiving what you want:

function resultArr = maxMinDiff(arr, windowSize)
    % If windowSize is greater than the actual arr, return 0
    if windowSize > length(arr)
        resultArr = zeros();
        
    % Else compute max - min for each window while sliding it.    
    else

        % Size of the window which is generated when computing max - min for each window while
        % sliding it across the array. The size depends on the actual arr and the window size.
        resultArr = zeros(1, length(arr) - windowSize + 1);

        % Special case for the first window.
        resultArr(1) = max(arr(1:windowSize)) - min(arr(1:windowSize));

        %Compute Max/Min for all subsequent sliding windows
        for i = 2:length(arr) - windowSize + 1
            maxCurrentWindow = max(arr(i:i+windowSize -1));
            minCurrentWindow = min(arr(i:i+windowSize -1));
            resultArr(i) = maxCurrentWindow - minCurrentWindow;
        end
    end
end

As I do not access to your data, I'm going ahead with an array containing randomnly generated numbers:

arr = randi(1000,1,10); % Generates random number array (with an upper bound of 1000) of size 1x10
windowSize = 5;

resultArr = maxMinDiff(arr, windowSize);

[Edward Ramirez]

Hello @Sourabh Kondapaka,

doesyour code work for a window which isn't a whole number? For example, suppose a window size of 0.8

[Sourabh Kondapaka]

Hi @Edward Ramirez,

window size only works for positive integers.