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I know that Ifft/fft are used in standard ofdm systems as a modulating/demodulating bases.Recently i've read that the orthogonality feature of DFT is also provided by Discrete Cosine Transform and by replacing Ifft stage with IDCT can give better peak to average power reduction.Can anyone explain how this happen?
Hi Tunelabguy, Refering to the steps in your previous post: = In step 4 the average must be taken or not depending on the scaling factor of the fft algorithm you are using. The important fact is that you need total power. = In step 5 you should multiply by 10 rather than 20 beacuse you have a power level yet Nevertheless, it seems that the A-weig
Calculate the RMS (Root Mean Square) it is the same as the standard deviation (1/n*Sum(value-average)^2
Hello one says that moving average filters (MAF) are good in the time domain (TD) and bad in freqeuency domain (FD). And that windowed-sinc filters are good in FD and bad in TD. But now I am wondering if in case of MAF it's nevertheless okay to transform the kernel and the data via fft to FD, doing there an elementwise multiplication and fina
I do not know what your "positivefft" is and a few other variables. At any rate, here is a simple code that calculates the average fft. I do not have matlab with me, so you might have to tweak it a little bit:Y_average=zeros(1,n); w=sum(windowHann); for m=0:9 Y=fft(x(1+m*n:n+m*n).*windowHann)*(2/w); (...)
Please not the textbook answer (my fft is 2^k (hardware reason) so because of guard bands it could be only a compact subset less than 2^k but greater than 2^(k-1))! I have found that there exists good preamble symbols for 2^k used carriers which have very low peak to average. Also binary channel subdivision for OFDMA is easier and adaptivity i
quantization noise can get from fft with trans sim, but you can't get others such as thermal noise , 1/f noise since the average to time is zero
Seems you have converted your waveform into the frequency domain by using the fft, which doesnt look to be necessary to caculate wavelgnth (λ). To get the wavelength, better to count zero crossings (after you have smoothened out your signal) and average over a sufficently long interval. That will give you the frequency. Assuming this is so
Hello DSP-ers, I am new to DSP and MATLAB and I have a project in which I am to take a signal and partition it into blocks of length L (# of samples) and perform an fft of each block and then ensemble average the fft of each. Anywhere to start would be helpful. I am able to read in the signal into MATLAB. I was also wondering if the (...)
hi there... can anyone help me in answering that what type of mean(average) is taken in selecting a center(carrier) frequency in the entire AM (audio frequency band) at which sampling can be performed for extracting a particular channel(radio frequency channel)... i'll be highly greatful if someone helped me in...
Hi Can someone guide me to the right algorithm to average magnitude in fft spectrum. Can this be done with n-point moving average filter without need to store last n frames of magnitude spectrum? Now I?m using exponential moving average algorithm ? Xavr = alpha*Xavr + (1-alpha)*Xnew. Is there similar formula for n-point (...)