Matlab Codes for Noise and Jammers

@silverscorpion • 07 Feb, 2009 what exactly do you want? code for noise generation or noise removal..
As to jammers, it's very easy. if you know the frequency you want to jam, you can generate some random signal of that frequency and greater amplitude. That's it.

If you dont know the frequency, then it becomes somewhat more difficult. Then you have to use hardware also. It cant be done only with matlab code. ie, use your receiver and receive the signal. know the frequency components in it and then generate that frequency. Clear?

@Vila • 08 Feb, 2009 Hii,

I need matlab codes for noise generation and also codes for broadband noise jammer.

Thank you...

@silverscorpion • 08 Feb, 2009 hey you!

I just answered your question and you are reposting the question again. I'll again tell you, we dont give you the code here. You do the code, if there are any problems, we'll be happy to help.

@durga ch • 08 Feb, 2009

Vila

Hii,

I need matlab codes for noise generation and also codes for broadband noise jammer.

Thank you...

what type of noise are you refering to?
gaussian?

@Vila • 09 Feb, 2009 Hiii,

Gaussian, AWGN or Broadband noise, either one can do..

Thank you.

@Vila • 09 Feb, 2009 Hiii,

Mmm well i have some codes here, its shows errors. to whom i have to show them to get rectified? Do i just post the codes here?

Thank you.

@silverscorpion • 09 Feb, 2009 just post that section of the code which has errors in it. Or if it's ok for you, posting the full code is no harm, either.. Post it in this thread itself.

@durga ch • 09 Feb, 2009

Vila

Hiii,

Mmm well i have some codes here, its shows errors. to whom i have to show them to get rectified? Do i just post the codes here?

Thank you.

If your matlab has communications tool box, you have function 'awgn' which generated white gaussian noise and adds it to your signal depending on the impedance and nosie DB

may be you can search the 'help ' section in your matlab for 'awgn' command

for more infomration you can as well refer to the MATLAB help link
Communications Toolbox Documentation

@Vila • 09 Feb, 2009 This program should show the effect of Gaussian filter.

%%%%%%%%%%%%% The main.m file %%%%%%%%%%%%%%%
clear;
% Parameters of the Gaussian filter:
n1=10;sigma1=3;n2=10;sigma2=3;theta1=0;
% The amplitude of the noise:
noise=0.1;
[w,map]=gifread('lena.gif');
x=ind2gray(w,map);
filter1=d2gauss(n1,sigma1,n2,sigma2,theta);
x_rand=noise*randn(size(x));
y=x+x_rand;
f1=conv2(x,filter1,'same');
rf1=conv2(y,filter1,'same');
figure(1);
subplot(2,2,1);imagesc(x);
subplot(2,2,2);imagesc(y);
subplot(2,2,3);imagesc(f1);
subplot(2,2,4);imagesc(rf1);
colormap(gray);
%%%%%%%%%%%%%% End of the main.m file %%%%%%%%%%%%%%%




When i tried to run them, it shows this error message:

Error in ==> gaussian at 7
[w,map]=gifread('lena.gif');

Thanks for helping...

@Vila • 09 Feb, 2009 These are another set of codes in which it should display Rayleigh function graph:


%Initialization D=1 (D = interleaving depth)
clear;
Ts=1/1e3; % tx rate = 10k bps
NA=10000;
A=floor(rand(1,NA)+0.5);
%A=randint(1,NA);
input=A;
G=[1 0 0; 1 0 1; 1 1 1];
k=1;

N=length(channel_output);
SNRdB= -10:5:20;
SNR=10.^(SNRdB/10);
Counter=zeros(1,length(SNRdB));
loop=0;

%***************************************************************
% AWGN + fading *
%***************************************************************
Fd=66; % Actual fading rate
fm=round(Fd*NA*Ts);

%Generate two inputs of 1 x N matrix
xin=randn(1,(NA+2)*3);
yin=randn(1,(NA+2)*3);

%Loop for all values of frequencies and truncate at just before f=fm
for f=1😔fm-1)
filter(f)=1.5/(pi*fm*sqrt(1-(f/fm)^2));
end
for f=(fm-1)😔NA+2)*3
filter(f)=0;
end

%Inputs of the filter is multiplied with the filter transfer function
xout=xin.*filter;
yout=yin.*filter;

%Perform inverse Fourier Transform on both output
xifft=real(ifft(xout));
yifft=real(ifft(yout));

% normaliation so that E{R^2}= 1 / in Watt = 0 dB
std_x=std(xifft);
std_y=std(yifft);
xifft=xifft/std_x/sqrt(2);
yifft=yifft/std_y/sqrt(2);

%Sum the square the of the IFFT and take the square root of it
rx=sqrt(xifft.^2+yifft.^2);

%****************************************************************
%Calculate for all value of SNRdB in AWGN + fading
%****************************************************************
loop=0;
for b=sqrt(SNR) %b is the signal level
loop=loop+1;
dfad=0;
for n=1😔NA+2)*3 %n = no of bits
x=randn;
t=channel_output(n);
if t>=0.5
a=b*rx(n);
r=a+x;
if r<0
dfad=dfad+1; % error has occured, increase counter
Df(n)=0;
else
Df(n)=1;
end
else
a=(-b)*rx(n);
r=a+x;
if r>0
dfad=dfad+1;
Df(n)=1;
else
Df(n)=0;
end
end
Counterf(loop)=dfad; % w/o decode
end
output=viterbi(G,k,Df); % E is output of decoder
zf=0;
v=1;
for v=v:1:length(A);
if xor(input(1,v),output(1,v))==1
zf=zf+1;
end
end
Counter_wcf(loop)=zf;
end% loop for signal (b) in AWGN + fading


%plot simulation in AWGN + fading without coding
Pef=Counterf/N;
%semilogy(SNRdB,Pef,'b');
%hold on;
%plot simulation in AWGN + fading with coding
Pe1f=Counter_wcf/NA;
save D1_66SNRdBPe1fPef
%semilogy(SNRdB,Pe1f,'b'); %D=1 no interleaving
%hold on;


but when i tried running them, it shows this error message:

Error in ==> Rayleigh at 12
N=length(channel_output);

Please help me..thank you

@silverscorpion • 09 Feb, 2009 In the first piece of code, try using imread() instead of gifread(). I'm not sure if a function gifread() to specifically read gif files exist.

In the second piece of code, you dont seem to have defined what is 'channel_output'. you have used channel_output as a function in the later part of the code, and in the top part, you have tried to find the length of a function. That might be the problem.

@durga ch • 09 Feb, 2009 I dotn see channel_output being defined. Did yu put up the whole code mate?

@Vila • 10 Feb, 2009 It gives the same error even if i use imread() instead of gifread()

Yes whole code mate, how do i define the channel_output then?

@durga ch • 10 Feb, 2009 Hi

clear;
Ts=1/1e3; % tx rate = 10k bps
NA=10000;
A=floor(rand(1,NA)+0.5);
%A=randint(1,NA);
input=A;
G=[1 0 0; 1 0 1; 1 1 1];
k=1;

N=length(channel_output);
SNRdB= -10:5:20;
SNR=10.^(SNRdB/10);
Counter=zeros(1,length(SNRdB));
loop=0;

if ts is your transmitted signal then your channle output should be a convolution of you input signal and noise.

ie your channel output should be on lines of
output = H * input;

where H is is your channel matirx and inout in Tx

@Vila • 11 Feb, 2009 Hiii thanks a lot,

Now i have a set of coding over here but i dont know how to determine which one is the information signal and which one is the carrier signal, wheter xin, yin, xout or yout..and what is NA?


%Initialization D=1 (D = interleaving depth)
clear;
Ts=1/1e3; % tx rate = 10k bps
NA=1000;
A=floor(rand(1,NA)+0.5);
%A=randint(1,NA);
input=A;
G=[1 0 1 1 0 1 1; 1 1 0 0 1 0 1; 1 1 1 1 1 0 1];
%G=[1 0 0; 1 0 1; 1 1 1];
k=1;
channel_output=cnv_encd(G,k,A);
N=length(channel_output);
SNRdB= -10:5:20;
SNR=10.^(SNRdB/10);
Counter=zeros(1,length(SNRdB));
loop=0;
L_one=length(G)-1;
no_rows=size(G,1);
encoder_output_bits=(NA+L_one)*no_rows;

%***************************************************************
% AWGN + fading *
%***************************************************************
Fd=2000; % Actual fading rate
fm=round(Fd*NA*Ts);

%Generate two inputs of 1 x N matrix
xin=randn(1,encoder_output_bits);
yin=randn(1,encoder_output_bits);

%Loop for all values of frequencies and truncate at just before f=fm
for f=1😔fm-1)
filter(f)=1.5/(pi*fm*sqrt(1-(f/fm)^2));
end
for f=(fm-1):encoder_output_bits
filter(f)=0;
end

%Inputs of the filter is multiplied with the filter transfer function
xout=xin.*filter;
yout=yin.*filter;

%Perform inverse Fourier Transform on both output
xifft=real(ifft(xout));
yifft=real(ifft(yout));

% normaliation so that E{R^2}= 1 / in Watt = 0 dB
std_x=std(xifft);
std_y=std(yifft);
xifft=xifft/std_x/sqrt(2);
yifft=yifft/std_y/sqrt(2);

%Sum the square the of the IFFT and take the square root of it
rx=sqrt(xifft.^2+yifft.^2);

plot(xout);
plot(yout);

Thank you mate...

@durga ch • 11 Feb, 2009

Vila

Hiii thanks a lot,

Ts=1/1e3; % tx rate = 10k bps
NA=1000;
A=floor(rand(1,NA)+0.5);
%A=randint(1,NA);
input=A;
G=[1 0 1 1 0 1 1; 1 1 0 0 1 0 1; 1 1 1 1 1 0 1];
k=1;
channel_output=cnv_encd(G,k,A);

hmm, tell me one thing has this code been picked off from the net?
anyways
A is your input signal. it s a randaom signal generated. NA can be any number and you rand 1,1000 .
and your G is the convoluional encoder in polynomial representation

@Vila • 12 Feb, 2009 Hiii...yes its from the net...if A is the input signal then how about xin and yin?

@stylishdudevicky • 22 Mar, 2010 Hi,
I know few people who can write any Matlab or programming codes as a pay service. contact them at coders.programmers@gmail.com
Hope this helps.

@robben71 • 05 Apr, 2011 Hi, does anyone have code for gray world and white point (image processing)?

@KrishTCE • 18 Feb, 2015 Hi...... i need the verilog code for generating jamming signal......... can anyone tell me the logic for generating???

@danish salim soonka • 20 Aug, 2016 i need to implement a jammer model can anyone help?