fft and frequency filtering

Started by ferhatdegirmenci in Matlab DSP14 years ago

I have a wav format audio file. I need to operate with fft and I have to filter it between 30hz to 100hz. I can read it, but I dont...

I have a wav format audio file. I need to operate with fft and I have to filter it between 30hz to 100hz. I can read it, but I dont know how to filter it. I don't know much about filters. Please help me


Choosing DSP Processor for FFT Application

Started by matl...@yahoo.com in Matlab DSP9 years ago

Hi DSP Gurus, I would like to build a Real Time FFT Display Unit for signals ranging from 3Khz to 150Khz. That device should be able to display...

Hi DSP Gurus, I would like to build a Real Time FFT Display Unit for signals ranging from 3Khz to 150Khz. That device should be able to display the frequency spectrum of the signals continuously. To achieve good frequency resolution, I need to compute 2048 Points FFT or even more. Now I need to select a DSP+ARM unit for this task, I am making modification to existing meter reader that operates ...


FFT/IFFT functions in Maltab & DSP same?

Started by vcte...@yahoo.com in Matlab DSP14 years ago

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?


Why this particular code doesnt work?

Started by Sreeram in Matlab DSP13 years ago 2 replies

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


FFT for complex data sequence

Started by mao mu in Matlab DSP16 years ago 3 replies

Greetings, Could anybody tell me if FFT works for complex sequences, and how to do it? If it doesn't, what other ways are...

Greetings, Could anybody tell me if FFT works for complex sequences, and how to do it? If it doesn't, what other ways are available? Thx! mu


FFT

Started by nitin lodhe in Matlab DSP13 years ago

Dear sir/madam, I need a code for FFT function that takes argument as follows ...

Dear sir/madam, I need a code for FFT function that takes argument as follows sfftmodel(rin,iin,N,THROUGHPUT,ARCH,DATA_PREC,TWIDDLE_PREC,INVERSE); Where- rin = real(x((i-1)*N + 1: i*N)); iin = imag(x((i-1)*N + 1: i*N)); ...


FFT in Matlab

Started by ngweelee in Matlab DSP18 years ago 1 reply

Hi guys, Can anyone please tell me how to perform fft on an array produced by matlab function 'wavread' and the result plotted...

Hi guys, Can anyone please tell me how to perform fft on an array produced by matlab function 'wavread' and the result plotted on a figure to get the pitch of the wav file? Any help is greatly appreciated. Thanks


Square wave with FFT

Started by litt...@yahoo.gr in Matlab DSP14 years ago

Hi to you all! I'm new in Matlab programming so i'll need some help. Well,i want to create a square wave where i can change the frequency...

Hi to you all! I'm new in Matlab programming so i'll need some help. Well,i want to create a square wave where i can change the frequency and afterwards make and plot the harmonics of the FFT. I've made something on my own but i have problems from the very begining. I'll really apreciate your help Thanks Can send and email in little_kostas153@litt...


problem with IFFT and sampling time

Started by saini_s1978 in Matlab DSP14 years ago

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


FFT and IFFT in OFDM

Started by ping...@hotmail.com in Matlab DSP14 years ago

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.


cleaning physiological data for FFT

Started by dsjo...@gmail.com in Matlab DSP8 years ago

Hi all, I'm new to DSP and Matlab and come from a non-engineering background (so go easy on me!), and have a few basic questions. As part of my...

Hi all, I'm new to DSP and Matlab and come from a non-engineering background (so go easy on me!), and have a few basic questions. As part of my psych studies im tracking the diameter of the pupil over 60s, at 60 samples a second. This is in response to stimuli of varying frequencies between 0 and 7 Hz. I plan to investigate the responses using FFT in Matlab My problem is that if someone bl...


FFT Zoom Transform

Started by g_rahame in Matlab DSP16 years ago 1 reply

Hi all Has anyone implemented the 'FFT Zoom Transform' in a m-code function? (ref. pg434 in 'Random Data: Analysis and...

Hi all Has anyone implemented the 'FFT Zoom Transform' in a m-code function? (ref. pg434 in 'Random Data: Analysis and Measurement Procedures' By J.S Bendat). Regards Graham


FFT bands

Started by dean_cvetkovic in Matlab DSP16 years ago

The work I'm doing is to simply determine the FFT analysis of four- chanell EEG signals. Can anyone tell me how can I calculate...

The work I'm doing is to simply determine the FFT analysis of four- chanell EEG signals. Can anyone tell me how can I calculate the individual (mean/max/min/median/sd) values of (3-8Hz),(8-13Hz), and (13-30Hz) ranges automatically and possibly plot it too for comparisons?


FFT Magnitude doubt

Started by Sonia Ramwaswamy in Matlab DSP16 years ago 3 replies

Hi everybody I wrote a simple code in MATLAB to find the FFT of signal ...

Hi everybody I wrote a simple code in MATLAB to find the FFT of signal ********************************************************** clear all; clc; Fs=100; t=[0:100]/Fs; s1=sin(2*pi*5*t); s2=sin(2*pi*10*t); s=(s1+s2); figure(1); p


spectrum and fft

Started by Sergio Dominguez in Matlab DSP17 years ago 4 replies

Hi all! Has anybody found anything strange working with the spectrum and fft functions implemented in matlab?? The...

Hi all! Has anybody found anything strange working with the spectrum and fft functions implemented in matlab?? The frecuency behaviour is OK, but there is some scaling factor missing. Basically I do not get the parseval theorem to apply when I find the spectrum wi


FFT comupation Reduction

Started by mortal_f in Matlab DSP9 years ago

Hi, I am trying to use fftfilt and my data contains a lot of zeros. I could recall from memory that if you are performing fft, and ur data...

Hi, I am trying to use fftfilt and my data contains a lot of zeros. I could recall from memory that if you are performing fft, and ur data contains a lot of zeros, you could reduce the computational load. Is this true? If it is, how could you do that? Regards


RE: FFT Magnitude doubt

Started by hahe...@gmail.com in Matlab DSP13 years ago

Hi Munish Can you explain the modified code for this lines? > S=fft(s,N)*(2/Fs); > w=((0:((N/2)-1))/(N/2))*(Fs/2); Thanks in...

Hi Munish Can you explain the modified code for this lines? > S=fft(s,N)*(2/Fs); > w=((0:((N/2)-1))/(N/2))*(Fs/2); Thanks in advance > > > > Hi Sonia > > I modified your code a bit. I think it will solve your problem. Try it. > > ____________________________________________________ > > clear all; > clc; > Fs=100; > t=[0:100]/Fs; > s1=5*sin(2*pi*5*t);


Non stationary Transient Data

Started by PANG...@ntu.edu.sg in Matlab DSP9 years ago 1 reply

Hi guys I have been trying to process my data with FFT to analyze the natural frequency of it. I try to use a high pass filter of 1 or 2 HZ...

Hi guys I have been trying to process my data with FFT to analyze the natural frequency of it. I try to use a high pass filter of 1 or 2 HZ because the source of the signal is a DC and i found that the result is still weird. It is a DC motor attach to a load and run it and will last for approximately 2 sec only. So i would like to ask the best DSP method to analyze this as if i just use FFT ...


magnitude of FFT of an image

Started by gandhi mathi in Matlab DSP17 years ago

Hai, how can I get the magnitude of the FFT of an image. gandhi

Hai, how can I get the magnitude of the FFT of an image. gandhi


fft

Started by tio tio in Matlab DSP16 years ago 1 reply

Dear Members, I acquired one-dimensional data by sound card of my PC with sample frequency 22050 Hz and period of observation...

Dear Members, I acquired one-dimensional data by sound card of my PC with sample frequency 22050 Hz and period of observation (duration) 30 s. I want to apply fft on the data and to plot the spectrum. I would like F to be with real values, not normalized values. I tried this: Y=