"when i used Matlab function i got the error message" Colon operands must be all the same type, or mixed with real scalar doubles.

Hello there !

This is my text.xlxs file

function Voltage = fcn(~)
coder.extrinsic('xlsread')

current =3; 
Signal=xlsread('test.xlsx'); % read from file  
frq= size(Signal,1);
S12= size(Signal,2);
for i=1 :Signal
    if (frq(i) == 2.4500 )
        x=S12(i);
    end
end
Power= x^2;
Voltage = Power/current;
end

It's keep show me this error when i run it " Colon operands must be all the same type, or mixed with real scalar doubles."

Actually I'm just a beginner in Matlab, So can you tell me please how can I fix it?

[Subhadeep Koley]

Hi, can you share your test.xlsx file? A first observation reveals that your definition of the indexing variable range i is not correct. The variable Signal is most probably a 2d matrix. Therefore you can not vary i from 1 to Signal.

[Walter Roberson]

notice that frq is a scalar double, but you are going to try to index it. You need to rethink your indexing

Answer 1

[Ayush Goyal]

From my understanding of the question you are facing issue while extracting columns of Signal matrix into separate vectors as frq and S12. You can refer to the following link for how to extract columns of a matrix into separate vectors:

https://www.mathworks.com/matlabcentral/answers/47632-how-to-extract-columns-of-a-matrix-into-seperate-vectors

Also, iterate your for loop from 1 to number of rows in Signal Matrix. Check the following code:

function Voltage = fcn(~) 
coder.extrinsic('xlsread') 
current =3;  
Signal=xlsread('test.xlsx'); % read from file   
frq= Signal(:,1); % Extract first column of Signal 
S12= Signal(:,2); % Extract second column of Signal 
for i=1:size(Signal,1) %Iterate upto number of rows in Signal 
    if (frq(i) == 2.4500 ) 
        x=S12(i); 
    end 
end 
Power= x^2; 
Voltage = Power/current; 
end