Issue defending a variable in MATLAB APP Desinger

I have a button taking a value from the user

% Value changed function: Freq_input2

function Freq_input2ValueChanged(app, event)

fm = app.Freq_input2.Value

app.Freqout.Value=fm;

end

and I defined fm in the main Properties as

properties (Access = private)

fm

amp

L

tread

p

end

Then I wanted to design a calculate (Push button) to perform certain analayiss,and I wanted to use this fm to calculate time vector

function Calculate_toggleButtonPushed(app, event)

fs=20*(app.fm)

N=10; % ?? For usage later on

t=-1:1/fs:1

m_k=app.amp*cos(2*pi*app.fm*t);

...

...

end

i get this error message

Error using /

Matrix dimensions must agree.

Error in NewGui/Calculate_toggleButtonPushed (line 118)

t=-1:1/fs:1

Error while evaluating Button PrivateButtonPushedFcn.

Answer 1

[Torsten]

If fs is a vector of values, you have to use elementwise division:

1./fs

instead of

1/fs

Same for

m_k = app.amp.*cos(2*pi*app.fm.*t);

instead of

m_k=app.amp*cos(2*pi*app.fm*t);

[Abdelrhman Abdelfatah]

that's what I did

fs=0;

fs=20.*(app.fm)

N=10; % ?? For usage later on

t=-1:1./fs:1

%

% m_k=app.amp.*cos(2*pi*app.fm.*t);

But it gives me fs as an empty vector, while i need it as one value scaler

Command Window output

fm =

1

fs =

[]

t =

1×0 empty double row vector

[Torsten]

fm is 1, but app.fm is empty.

[Abdelrhman Abdelfatah]

then how can I call the value of fm?

I thought I would just use app.fm no? because it's decalred inside another function

[Walter Roberson]

You are assigning to local variable fm in the function, not to app.fm. The function does save the value but into a different location, not app.fm