hi I'm currently working with my musical fountain project and initially managed to program in Matlab. My procedures are: 1. Wavread a...

hi I'm currently working with my musical fountain project and initially managed to program in Matlab. My procedures are: 1. Wavread a wavfile having 44KHz FS. 2. FFT process every 22K samples to managed half a second wav data. 3. I used 44K fft points. 4. I used only the first 22K fft points because ffting produces double image. 5. Obtain 8 frequency ranges (bands). Is my process cor...

Hello DSPers, Can someone please give me pointers to an efficient implementation of the FFT on a C16x microcontroller? I have tried google...

Hello DSPers, Can someone please give me pointers to an efficient implementation of the FFT on a C16x microcontroller? I have tried google and the only option I find is the KISS fft. Are there any better strategies? Thanks and best regards. Ravi.

I am designing a system using sonar, the requirement of which are given below: Transmittin frequency : 50 KHz Received Echo Frequency to be...

I am designing a system using sonar, the requirement of which are given below: Transmittin frequency : 50 KHz Received Echo Frequency to be detected : 45-55 KHz Frequency Resolution : 90 hz Sampling Rate : 250 KHz If I use fft, We have to use a fft with a huge number of points. To get this resolution, we need (250KHz/(90/2))= 5556 point fft. And this is the limitation. We do not want t...

When I normally do a FFT, the frequency resolution = sampling frequency/number of samples. When I use windowing (like BH4) to prevent smearing,...

When I normally do a FFT, the frequency resolution = sampling frequency/number of samples. When I use windowing (like BH4) to prevent smearing, this should increase the frequency resolution of the FFT, because of the convolution in the frequency domain. I have seen tables which show the frequency resolution increases by a factor of 1.9 for a Blackman Harris window, so if the frequency resoluti...

Hi, I want to compute e.g. 8192 point FFT from signal that is sampled with Fs = 48kHz, but 8192 samples (or 4096) should represent frequencies...

Hi, I want to compute e.g. 8192 point FFT from signal that is sampled with Fs = 48kHz, but 8192 samples (or 4096) should represent frequencies e.g. 2500Hz to 3000Hz. I will need to implement it in SHARC DSP, therefore to compute huge FFT from 0 to 48kHz and then take a small part (2.5kHz-3kHz) is not an effective way. Is there any effective way? Thanks, Afi

Hi! I am using a MicroChip Dspic30 for sampling data, the data is about 10 to 30 kb and is after sampling stored in a external flash. Now i...

Hi! I am using a MicroChip Dspic30 for sampling data, the data is about 10 to 30 kb and is after sampling stored in a external flash. Now i want load this data and perform FFT on this data to calculate the maxiumum frequency. The problem is that i only have about 1kb data memory left. So the question is how to perform FFT whis this small data memory, have anyone tried it and made i working ...

I need to analyze the magnitude spectra of some data sets. Every data vector will have 128 or fewer complex samples. I window all the...

I need to analyze the magnitude spectra of some data sets. Every data vector will have 128 or fewer complex samples. I window all the data using a Chebyshev window with a certain level of relative sidelobe attenuation. Normally, I zero pad the windowed data and take a 128-pt FFT. Now I'm experimenting with longer FFTs (256 and 512) in an attempt to get a higher resolution look at the spec...

> Do you mean correlating the cyclic prefix against the delayed signal > or a specific preamble? In either case, though, the processing is >...

> Do you mean correlating the cyclic prefix against the delayed signal > or a specific preamble? In either case, though, the processing is > done at baseband so the signal is complex. U mentioned processing is done at baseband, meaning the correlation is done after FFT at the receiver? but most blocks i c have their estimation and synchronization blocks before FFT. The ones after FFT are

Hello all, I am not able to get the correct amplitude of input signal from DFT. My sampling frequency is 128Hz and I am take 128 Samples and...

Hello all, I am not able to get the correct amplitude of input signal from DFT. My sampling frequency is 128Hz and I am take 128 Samples and computing 128-point FFT. I also have a simulated sine wave generator which I am using as input. When I vary the input frequency, FFT detects the frequency correctly till 64Hz (i.e. Fs/2) but it gives different amplitude values for different frequencies even ...

Hi, I'm new on this. I want to analyze a sinusoid function using FFT algorithm provided in Matlab. So, I found the following coding from this...

Hi, I'm new on this. I want to analyze a sinusoid function using FFT algorithm provided in Matlab. So, I found the following coding from this forum and i'm thinking to use it to analyze the signal. Anyway, I have some doubt about this coding. The coding is: clear all; clc; Fs=100; t=[0:100]/Fs; s1=5*sin(2*pi*5*t); s2=10*sin(2*pi*10*t); s=s1+s2; figure (1); plot(t,s); N=2560; S=fft(s,...

Hi all! I have fd=65KHz. I do fft with window Hann 4096 points. I need detect frequency 12kHz...20kHz with resolution 2 Hz. What must I do? I...

Hi all! I have fd=65KHz. I do fft with window Hann 4096 points. I need detect frequency 12kHz...20kHz with resolution 2 Hz. What must I do? I understand that i must mix input signal with 12 kHz sine. How?

Hi I am looking for an optimal FFT algorithm with low computation complexity and significant simplicity for hardware implementation. there...

Hi I am looking for an optimal FFT algorithm with low computation complexity and significant simplicity for hardware implementation. there are several FFT algorithm like Cooley-Tukey or Prime-factor or Split-radix ... each have several version with different complexity. would you mind to help me for finding better algorithm ?

Hi; I have an algorithm in VBA that: -takes the sampled (500-1000 Hz) Torque signal, and splits it up into sections that correspond to each...

Hi; I have an algorithm in VBA that: -takes the sampled (500-1000 Hz) Torque signal, and splits it up into sections that correspond to each revolution of the machine. - For each revolution of torque data, I interpolate the data to fit a power of 2 samples for the FFT algorithm. - I take the FFT of each revolution of torque data, and then chop all but the 1st 4 orders of the spectrum. ...

Hi DSP Team, I am attempting to use excel?s FFT analysis to remove the seasonal and annual signals (noise) in long monthly sea level records as...

Hi DSP Team, I am attempting to use excel?s FFT analysis to remove the seasonal and annual signals (noise) in long monthly sea level records as part of current sea level rise studies. I have successfully used the FFT function in excel to identify high frequency (repetitive) signals of interest. I was wondering however, if there is a way of separating or isolating these particular signals, rem

Someone has posted in the group how to detect pulses or spikes. It seems that the idea is to compare the output of two different FFT. A...

Someone has posted in the group how to detect pulses or spikes. It seems that the idea is to compare the output of two different FFT. A long term and a short term. But how can I do that? I'm doing a real-time analysis and i need to detect the spikes or pulses. I thought about doing a 1024 point FFT and a 64 point FFT and compare their outputs... But i don't really know how. In fact, thes...

I am relatively new to DSP and I have what seems like a simple question, but I have not been able to find in answer to it by reading DSP...

I am relatively new to DSP and I have what seems like a simple question, but I have not been able to find in answer to it by reading DSP books. If the goal is to design a frequency-selective filter, then is there any reason not to simply take the FFT of a signal (or a window thereof), apply our filter by directly multiplying the filter amplitude response with the FFT of our signal, and the...

Hi, I have checked. the first input sample is fed in when index for xn is 3. I have followed the timing. But i found something further....

Hi, I have checked. the first input sample is fed in when index for xn is 3. I have followed the timing. But i found something further. The problem is due to the FFT result. Did you do this the last time? 1) generate 24 bit number 2) feed into the FFT 3) the 34 bit result which you obtain in VHDL testbench is piped into a text file. afterward, you IFFT the result in matlab the...

Hello!!! I need help using FFT functions, i've made a simple C program thats reads out the header of a wave file and it also reads the data chunck...

Hello!!! I need help using FFT functions, i've made a simple C program thats reads out the header of a wave file and it also reads the data chunck to a char *data array, but i still can't perform FFt to it, i think that i am making some mystakes in my c prog. I know that the data chunck is good, because i can play the file using the .NEt library. I'm trying to do the following: for (int ...

i have problem regarding dividing two signals in frequency domain using fft.i m just taking fft of two signals and then taking division...

i have problem regarding dividing two signals in frequency domain using fft.i m just taking fft of two signals and then taking division like fft_s1./fft_s2 should i use some preprocessing filter before division? any suggestion or any one who has encountered and solved this problem?

I'm looking for a simple (need not be very efficient) VC++/C++ library that does the image (png) convolution, 2D FFT. I would like to develop a...

I'm looking for a simple (need not be very efficient) VC++/C++ library that does the image (png) convolution, 2D FFT. I would like to develop a image search feature (http://www.dspguide.com/ch24/6.htm) with a VC+ + based GUI around it. http://www.codeproject.com/KB/graphics/ImageConvolution.aspx does have the convolution feature but not FFT. Anybody gone through the same requirement? Thank...