Hi all, I have some problems in simulating the OFDM using matlab. I will list them one by one. 1). Normailsation of the signal after ifft...

Hi all, I have some problems in simulating the OFDM using matlab. I will list them one by one. 1). Normailsation of the signal after ifft & fft. Do we have to multiply by any factor after taking the ifft and fft in the matlab?. Please explain me about this for the OFDM symbol with Useful Subcarriers. 2). Finding the NoiseVariance in to create the

Can we use directly the FFT and IFFT functions in Matlab for OFDM simulation? I found IFFT(AWGN) will result in strange mean and variance. ...

Can we use directly the FFT and IFFT functions in Matlab for OFDM simulation? I found IFFT(AWGN) will result in strange mean and variance.

I'm currently doing a project on OFDM signal generation. I plan to write my codes in Matlab and later convert it into C and then download...

I'm currently doing a project on OFDM signal generation. I plan to write my codes in Matlab and later convert it into C and then download it into DSPs. My question is, when i use the fft/ifft functions that come with Matlab, when i convert it and download it into the DSP. Will it have any problem? Will the fft/ifft operation be same on the DSP?

Hi everybody, My problem is as follows: I get data from a fft analyser after numerous averaging in order to remove the noise. Now in...

Hi everybody, My problem is as follows: I get data from a fft analyser after numerous averaging in order to remove the noise. Now in order to use it i have to take the IFFT of this data in Matlab. But fft analyser(any) while taking fft take sampling frequency as 2.56 times the maximum frequency specified. But when IFFT is taken in matlab it will just do

sig=wavread('path to signal...

sig=wavread('path to signal file'); reconstructed_sig=ifft(fft(sig)); subplot(2,1,sig); plot(sig); subplot(2,2.reconstructed_sig); plot(reconstructed_sig); i know that to analyse the fft of sig, the magnitude and phase spectra of it must be found.But why is the ifft-fft combination not working? What must i do so that i can reconstruct the original sig using ifft? Thanx in advance warrier

Hi!! I am new to matlab so please bear with me. I don't understand the IFFT and FFT matlab functions. Here is the code i am...

Hi!! I am new to matlab so please bear with me. I don't understand the IFFT and FFT matlab functions. Here is the code i am using: [sig,fs]=wavread('aemixed.wav'); time=(1:length(sig))'/fs; figure(1) plot(time,sig) fsig1 = fft(sig,fs); Y=real((ifft(fsig1,length(sig)))); figure(3) plot(time,Y) What I don't understand is that Y and sig are not the same. Can someone please explain...

i want to compute the ifft of the following data data=[0 1 1 0] in matlab it should return me a single value but it is giving me a...

i want to compute the ifft of the following data data=[0 1 1 0] in matlab it should return me a single value but it is giving me a column of values can anybody explain this to me and secondly how matlab carries out the ifft , how can it be done by hand to verify the result thanks

Hi, I want to ask if I FFT an image, how can I recover the image using IFFT. I try to use it directly, but turn out some a totally...

Hi, I want to ask if I FFT an image, how can I recover the image using IFFT. I try to use it directly, but turn out some a totally bright picture. However, when i change the image to a very simple one, say only black and whit region, ifft can receover the image. I find out from

Here is the code snipet i need help with... for i = 1:end_frame for j = 1:1024 fout(i,j) = ifft(Z(i,j)); end end As...

Here is the code snipet i need help with... for i = 1:end_frame for j = 1:1024 fout(i,j) = ifft(Z(i,j)); end end As you can see, if the end_frame is large, the for loop would take so long. What alternatives can I do? I've tried fout = ifft

Hi guys this is "my first" ofdm code.could you tell me how it is and how to add the cyclic prefix? Another question is: in the function ifft...

Hi guys this is "my first" ofdm code.could you tell me how it is and how to add the cyclic prefix? Another question is: in the function ifft should i insert the IFFT SIZE? %--------1---------2---------3---------4---------5---------6---------7---------8 % OFDM Simulation clear all; close all; % % Basic OFDM system parameters % - choice of defaults or user selections % fprintf ('OFDM...

I have a question. There is a signal which x-axis is freq. and y-axis is Power Spectrum Density. After convert this freq. domain...

I have a question. There is a signal which x-axis is freq. and y-axis is Power Spectrum Density. After convert this freq. domain signal to time domain(using IFFT), the x-axis is time, how about the unit in y- axis? Thank you.

Hi, i've forgotten where i read about this but i know for OFDM, if i want the output of my IFFT to be real, i can only use half of...

Hi, i've forgotten where i read about this but i know for OFDM, if i want the output of my IFFT to be real, i can only use half of the subcarriers with the other half the complex conjugate mirror of the 1st half. It apparantly got to do with the properties of Fourier transform or something like that. I'm currently writing my report on OFDM. Can someone direct me to references or literature...

Hi all ,=20 I am trying to implement IFFT in vhdl . I tried to use the=20 matlab , but not sure how can i get the twiddle factor ....

Hi all ,=20 I am trying to implement IFFT in vhdl . I tried to use the=20 matlab , but not sure how can i get the twiddle factor . Is it=20 possible to get the twiddile factor in fixed point from matlab so that=20 i can use it in vhdl code directily? Thanks in advance. John=20 =20 =20

I am doing a project regarding OFDM.I used 64 QAM to modulate the data . The output of QAM is complex. Can the complex output be given...

I am doing a project regarding OFDM.I used 64 QAM to modulate the data . The output of QAM is complex. Can the complex output be given directly to perform IFFT ?

so i'm venturing into communications research and i'm stuck on how to change symbols into the time domain. i have modulated bits, say [0...

so i'm venturing into communications research and i'm stuck on how to change symbols into the time domain. i have modulated bits, say [0 1] which in bpsk is just -1 and 1. how do i take this data and put it on the time domain to be transmitted? it should just be a sine wave and then at one point be shifted over 180 degrees. it was my understanding that you throw the IFFT in there to accomp...

hi all, i'm trying to plot ofdm normalized (dBr) psd after ifft function. i.e: carriers=NFFT.*ifft(tx); %plot normalized PSD i've tried...

hi all, i'm trying to plot ofdm normalized (dBr) psd after ifft function. i.e: carriers=NFFT.*ifft(tx); %plot normalized PSD i've tried pwelch(), psd() and their varients but my results do not match the theory. i'll appreciate some help on the subject. thanks.

Hi all! My question is about getting the impulse response from the transfer function of a system. I have simulation data for the transfer...

Hi all! My question is about getting the impulse response from the transfer function of a system. I have simulation data for the transfer function of an LTI system. I make the data Hermitian symmetric so that when I do an IFFT on it, I get a real impulse response. So far so good. But the problem is the shape of the impulse response I get after the IFFT. It oscillates at the beginning, decays t...

? Please i need? help in PSD to compare between different methods of PAPR. When apply the following code not given the same plot as in your...

? Please i need? help in PSD to compare between different methods of PAPR. When apply the following code not given the same plot as in your paper . ? My Matlab code ? N = 256;????? % length of OFDM IFFT M = 16;?????? % number of QAM constellation BW=10;??????????? % in MHz txData= randint(N,1,M); txDataMod? = qammod(txData,M); ? txDataZpadIfft = sqrt(N)*ifft(txDataMod ,N); ...

Hi Please see this code , I am confused how i added the two version of signal received from two Taps with one sample delay.Initially I have...

Hi Please see this code , I am confused how i added the two version of signal received from two Taps with one sample delay.Initially I have done IFFT of the signal with Four subcarriers.Please guide me. x=transdata1; taps=2; p1=1; p2=0.8; gain1=sqrt(p1/2)*[randn(1,length(x)) + j*randn(1,length(x))]; gain2=sqrt(p2/2)*[randn(1,length(x)) + j*randn(1,length(x))]; channel_ifft=ifft([gain1,ga...

Hi, I am working on an OFDM system using Matlab. The bits received at the receiver have a constant error ( i.e., avg 200 bits out of 1000 are...

Hi, I am working on an OFDM system using Matlab. The bits received at the receiver have a constant error ( i.e., avg 200 bits out of 1000 are always wrong).. when I decreased no. of bits in a symbol to let say 49 and FFT length to 64, there was no error. It looks like that there is some error in the computation of IFFT/FFT bolcks by Matlab (maybe some rounding of the data by Matlab). I am unsu...