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#### disney_snoopy

##### Newbie level 6
fm demodulation

Hi all,

Need your advise on how to write a program for the FM demodulation.
Please do explain here or with an attachment!!!
Thankz.

matlab fm modulation

do you need it using matlab?

matlab fmmod

Aya2002 said:
do you need it using matlab?

Yes. Either use MAthCad or Matlab.
I need a Fm demodulation after i modulate my analog signal to FM signal of using FM modulation.

fm demodulation in matlab

My Friend,

If you have matlab installed on your computer you can search with its help, for example see the following:

fmmod

Frequency modulation
Syntax

y = fmmod(x,Fc,Fs,freqdev)
y = fmmod(x,Fc,Fs,freqdev,ini_phase)
Description

y = fmmod(x,Fc,Fs,freqdev) modulates the message signal x using frequency modulation. The carrier signal has frequency Fc (Hz) and sampling rate Fs (Hz), where Fs must be at least 2*Fc. The freqdev argument is the frequency deviation constant (Hz) of the modulated signal.

y = fmmod(x,Fc,Fs,freqdev,ini_phase) specifies the initial phase of the modulated signal, in radians.
Examples

The code below modulates a multichannel signal using fmmod and demodulates it using fmdemod.

Fs = 8000; % Sampling rate of signal
Fc = 3000; % Carrier frequency
t = [0:Fs]'/Fs; % Sampling times
s1 = sin(2*pi*300*t)+2*sin(2*pi*600*t); % Channel 1
s2 = sin(2*pi*150*t)+2*sin(2*pi*900*t); % Channel 2
x = [s1,s2]; % Two-channel signal
dev = 50; % Frequency deviation in modulated signal
y = fmmod(x,Fc,Fs,dev); % Modulate both channels.
z = fmdemod(y,Fc,Fs,dev); % Demodulate both channels.

this is from matlab help.

also you can find the digital mode of all the modulation types.

Regards

fm modulation matlab

Aya2002 said:
My Friend,

If you have matlab installed on your computer you can search with its help, for example see the following:

fmmod

Frequency modulation
Syntax

y = fmmod(x,Fc,Fs,freqdev)
y = fmmod(x,Fc,Fs,freqdev,ini_phase)
Description

y = fmmod(x,Fc,Fs,freqdev) modulates the message signal x using frequency modulation. The carrier signal has frequency Fc (Hz) and sampling rate Fs (Hz), where Fs must be at least 2*Fc. The freqdev argument is the frequency deviation constant (Hz) of the modulated signal.

y = fmmod(x,Fc,Fs,freqdev,ini_phase) specifies the initial phase of the modulated signal, in radians.
Examples

The code below modulates a multichannel signal using fmmod and demodulates it using fmdemod.

Fs = 8000; % Sampling rate of signal
Fc = 3000; % Carrier frequency
t = [0:Fs]'/Fs; % Sampling times
s1 = sin(2*pi*300*t)+2*sin(2*pi*600*t); % Channel 1
s2 = sin(2*pi*150*t)+2*sin(2*pi*900*t); % Channel 2
x = [s1,s2]; % Two-channel signal
dev = 50; % Frequency deviation in modulated signal
y = fmmod(x,Fc,Fs,dev); % Modulate both channels.
z = fmdemod(y,Fc,Fs,dev); % Demodulate both channels.

this is from matlab help.

also you can find the digital mode of all the modulation types.

Regards

Hi aya,

The code that u gv me as example, i paste it in M-files but when run it; it has error on the line 8.
y = fmmod(x,Fc,Fs,dev); % Modulate both channels.

May i know why it has error? Is it i shouldnt paste it in M-files?

Regards,

fm modulation and demodulation in matlab

Hi friend, I checked it, there are no errors with the above program

by the way, this is from matlab help not from me so that it is impossible to have an error.

thanks

matlab commands for fm modulation

Hi please see my mathlab attachment... i print screen the M-file and my command window that show me error.

However, my M-file line 3 does have a []bracket error of red colour line...

matlab programme on frequency modulation

which matlab version are you using?
have you checked which of the input data is of a 'double' type and why?

one more thing,
as this is an example straight from the matlab help, go to your matlab help and check what example is given there should be something similar, with probably very minor differences im using MathLab R2007b.

So u mean only type help in my command window?
as i type help in my command window and it promt out alot of command but no fm demodulation command.

Or choose what from the help icon?

Or can you all print screen for me ur source code with the output?

matlab fm source

try help using F1 it should lead you to the help, where you can use for example 'search' option to go to the help about fmmod option, there I can find in my matlab (7.1) exactly the same example that Aya2002 pasted above. Check what do you have there if you are using the help from the command window you can print help fmmod but you won't get the example there, so use F1 option (or choose the question mark from menu ).

good luck
A.

frequency modulation command in matlab

I agree with jamalenka 100% do every thing said by him/her fm modulation m-file

cannot also... it stated no match found!!!
anyhow, can any1 tell me why my source code got error?

ok i get the output... Different version is defferent source code.

Anyhow i need to convert it to mathcad but i doesnt know how to convert it to mathcad.
Can anyone help me on this???
All i need to do is write the FM demodulation formula to MathCad.

Thankz

fm demodulation formula

Any formula to do 2 get the demodulated signal as in the mathlab?
All i can found in book and on9 or e-book is talk all bout the demodulation SNR, noise error and etc.

But i need a formula to draw out my graph is the demodulated signal of "frequency versus time"...

I would very gratefull if you all would help.

Thankz.

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