246 Threads found on edaboard.com: Calculate Fft
I am looking for a software to calculate fft. In order to have an idea about SFDR .
Does anyone know a good one (free would be great)?
Thanks a lot.
Software Links :: 30.01.2010 05:52 :: fasto2008 :: Replies: 1 :: Views: 439
I'm new to DSP. I'm trying to calculate fft for an ADC. I captured the digital output from the ADC by using a Digital comparator and stored the output code in a file. I need to know how i can use this digital output codes(1's and 0's) to calculate fft , as fft needs real and imaginary (...)
Digital Signal Processing :: 15.06.2010 08:23 :: wks_19 :: Replies: 2 :: Views: 1303
How to calculate fft core SQNR?
Sounds very easy but seems it is not.
I have a Verilog RTL core for fft.
I have a very accurate reference model for fft.
Let's assume that my RTL core outputs are R0, R1, R2.......Rn.
And reference model outputs are M0, M1, M2.......Mn.
Having these samples how can I (...)
Digital Signal Processing :: 01.03.2011 10:33 :: Syswip :: Replies: 2 :: Views: 1159
How do we caluculate fft from a group of sampled values
Iam interested to calculate frequency from fft.What happens to the imaginary term in the fft in real time.
Any basic DSP text book can give you the equation for DFT and fft algorithms like Radix2 and Radix4. Once you (...)
ASIC Design Methodologies and Tools (Digital) :: 17.01.2005 10:29 :: eda_wiz :: Replies: 7 :: Views: 1377
I am trying to develop a function in Matlab to calculate fft using DIF RADIX 2. In order to test it , firstly I am working with a signal with length =8 x= . Unfortunatelly it is not returning the correct result, I cant find what is wrong with the algorithm.
If somebody realise what is wrong in the code below, please let
Digital Signal Processing :: 21.10.2005 22:24 :: claudiocamera :: Replies: 1 :: Views: 5916
now I want to take DFT.
is it true:
dft(sample("out" 2ns 22ns "linear" 100ps) 2ns 22ns 128 ...)
wil this calculate fft?
Digital Signal Processing :: 22.12.2006 02:53 :: hr_rezaee :: Replies: 10 :: Views: 1112
I am trying to calculate fft on the PIC16F877A, since the PIC can't provide enough RAM. I have store each calculation to the SRAM.
Here is the sample code.. I still can't get it to work though...
Any help would be great...
//Source code from here:
//the adc input data is
Digital Signal Processing :: 06.12.2007 06:14 :: slickuser :: Replies: 3 :: Views: 5028
I have been trying to calculate fft based on Radix-4 in Excel. Also I have been comparing my result with matlab. But I am stuck at the moment because I felt something did not seem to be correct. Please find the attached file.
Any help would be appreicate
Digital Signal Processing :: 09.07.2009 06:01 :: Maverickmax :: Replies: 1 :: Views: 1072
I have been implementing OFDM with fixed-point fft. I have 16 bits at Tx output for DAC, but I have only 6 bits ADC for Rx. As you can see below
At Tx.....Outout from FPGA 16 bits then connected to DAC .........
At Rx....ADC with 6bits input to FPGA for fft processing.
Therefore, the problem is how to process and (...)
Digital Signal Processing :: 26.11.2009 16:00 :: kpuntsri :: Replies: 4 :: Views: 787
i need to calculate fft of the sinusoidal output of incremental ADC with 16 bit resolution
In order to achieve sinusoidal output vs input samples, i gave ramp input voltage amplitude from 0 to 3V for 20000 samples in sin function with fixed frequency freq =1 and fs = 60K with ADC cycles 257 and veried the phase from 0 to 2pi.
ASIC Design Methodologies and Tools (Digital) :: 06.01.2012 13:15 :: singhji0000 :: Replies: 0 :: Views: 608
While comparing two approaches to calculate fft, better to use identical data with 2^n (say 1024) points. The outcome should agree. You can do that using your own program. availability of a sample data will also help more quantitative responses. You may try math cad too.
Electronic Elementary Questions :: 01.04.2012 18:45 :: ark5230 :: Replies: 3 :: Views: 1219
i am trying to use 3gsps adc of e2v's ev10as152a, the datasheet is claiming that this adc can give upto 5GHz bandwidth (better SFDR even in 2nd and 3rd Nyquist zones). but when i calculate fft for this digital data(after down sampling) i can only get Fs/2 bandwidth i.e i can only get upto 1.5Ghz frequency calculation. How can i (...)
Digital Signal Processing :: 06.08.2013 09:20 :: appalanaidu :: Replies: 0 :: Views: 465
I want to build a harmonic current meter for power supply testing,I use AD converter to sample AC input current ,but how can i calculate harmonic current ? what is the formulate? how to use fft?
Professional Hardware and Electronics Design :: 12.02.2004 22:19 :: alphi :: Replies: 3 :: Views: 2255
Would greately appreciate some advice.
If I have say 256 sample of a digitized waveform.
Is it possible to calculate the frequency from these sample ?
Any info wouls be much appreciated.
Digital Signal Processing :: 19.07.2004 13:01 :: jimbies :: Replies: 3 :: Views: 2839
Somebody can tell me !! How to calculate SNDR of ADC??
How to find Matlab program that to analysis dynmic parameter of A/D Converter ??
Analog Circuit Design :: 03.09.2004 02:11 :: chrischen :: Replies: 3 :: Views: 3296
THD is simulated by percent,while noise is nv^2/hz,how to get the THD+N by percent??? :) thanks first!
Analog IC Design and Layout :: 27.10.2004 07:12 :: nickooeda :: Replies: 2 :: Views: 2377
Yeath , you are right.
In the mean while , i know the step frequency (approximating delta frequency=2/(Tstop)) , by it , we can calculate the point number for frequency range estimated by fft .
But the frequency step effects the time of estimation and the accauracy. How does we select the step as resonable as possible . Is there e
Analog Circuit Design :: 01.01.2005 00:33 :: andy1 :: Replies: 4 :: Views: 1005
Is possible to calculate theorically Swtiching transients from Spectrum due to modulation by taking into account the rising and falling edge of the burst ramp? Is there any theorical calculation of Switching due to transients in GSM?
Is there any paper about this subject?
thank you for your help.
RF, Microwave, Antennas and Optics :: 25.04.2005 15:46 :: Rafouille :: Replies: 2 :: Views: 1015
you should got the final value of S/H output at each hold phase. Then perform fft to calculate the SNDR & ENOB.
Analog Circuit Design :: 10.07.2005 12:23 :: Lantis :: Replies: 4 :: Views: 1789
I need help for my pipelined ADC. I sampled the output and used matlab to get fft. Using the program in this forum, I calculate SNR,THD,etc. But I have problem during this procedure. I sampled the single sin wave, using Matlab code, SNR is just about 100dB. But when I tried to sampled the ouput from ideal DAC(I tested the example in Baker's book(mi
Analog Circuit Design :: 12.08.2005 22:50 :: tyd :: Replies: 8 :: Views: 3958
I have designed a second order sigma delta for sampling frequency of 12.8MHz and OSR=256 in Hspice. I don't know how to calculate the SNDR. I mean how to set these parameters: input frequency,transiation step and N (# of fft points).
Thank you in advance,
Analog Circuit Design :: 14.08.2005 02:50 :: tatakt :: Replies: 4 :: Views: 1692
There is no differennce between DFT and fft. Both operations do the same thing, but fft is faster in computation than DFT. Actually, in fft, a divide and conquer approach is used to calculate the DFT. The algo for calculating fft is as follows:
For a length N complex sequence , , the discrete (...)
Digital Signal Processing :: 12.12.2005 00:17 :: shameem :: Replies: 3 :: Views: 2941
I am design a 10bits pipeline ADC and by followingprevious articles I use Matlab to do fft. But here are the problems I met.
N=8192(number of data points in fft),
M=83 (integer number of cycles within the sampling window),
First I used coherent sampling method to do fft and I got a result, freqd_1. (...)
Analog Circuit Design :: 17.01.2006 04:17 :: yushen_yang :: Replies: 1 :: Views: 1147
I'm not sure either.
But i do remember that Ali Niknejad, a Professor at berkeley, said something about this during one of his
lectures last semester. He said sometimes , people think they are looking at the phase
noise, but its not acutally the phase noise, its the distortion due to the windowing effect of running the simulation for only a
Analog Circuit Design :: 07.02.2006 03:24 :: eecs4ever :: Replies: 3 :: Views: 1254
For a sine wave generated by PLL, can anyone tell me how to calculated its SNR?
In the frequency spectrum , I can not distingguish what's the signal and what's the noise because the signal spectrum is not a single line but with a lot of phase noise.
As a common method, in fft analysis, we often pick some bins beside the signal and add them toget
Analog Circuit Design :: 05.03.2006 22:20 :: sixth :: Replies: 2 :: Views: 1295
The SNDR can be calculated by the calculator in spectreRF. For the SNR, you need to exclude the distortion products shown in the spectrum. Remember, it is not the distance from signal peak to noise floor -- this distance is usually called SFDR (spurious free dynamic range). Only knowing the noise floor is not sufficient, you also need to know how m
Analog Circuit Design :: 09.04.2006 13:56 :: willyboy19 :: Replies: 12 :: Views: 11056
This computes an in-place complex-to-complex fft
x and y are the real and imaginary arrays of 2^m points.
dir = 1 gives forward transform
dir = -1 gives reverse transform
short fft(short int dir,long m,double *x,double *y)
/* calculate (...)
Digital Signal Processing :: 05.05.2006 07:05 :: sanbaba :: Replies: 0 :: Views: 664
performing convolution using fft (so-called fast convolution) is faster than direct convolution.
If you have two sequencies of length N, the complexity of direct convolution is of the order of N^2.
With fast convolution, you have to perform two fft's (direct and inverse), that have complexity of the order of N*log2(N), plus spectr
Digital Signal Processing :: 17.05.2006 18:19 :: zorro :: Replies: 2 :: Views: 1666
how to calculate the SNR and SNDR of the bit stream (1-bit stream) of sigma-delta modulator, and the SNR and SNDR of the output data of the all ADC. need your helps. Thanks in advance.
Analog IC Design and Layout :: 01.06.2006 02:49 :: wonbef :: Replies: 4 :: Views: 1656
Currently, im designing 8-point fft. From my view, we must calculate two values within the stages of fft which is block offset and stride. Can anyone explain to me what it means by stride and block offset.
Digital Signal Processing :: 30.06.2006 14:54 :: siva_7517 :: Replies: 0 :: Views: 917
Yes,u can. u will get the various frequency component of signal included in the text file by fft.
the program below will be helpful to you
to calculate fft
Analog Circuit Design :: 12.10.2006 05:10 :: heartwide :: Replies: 3 :: Views: 785
how many sample number you take to calculate fft?
for a 12 bit ADC, you should take 2^13 sample at least.
Analog Circuit Design :: 04.11.2006 04:26 :: nathanee :: Replies: 6 :: Views: 1556
im confused with fourier transform of discrete signals. how do we calculate it
Digital Signal Processing :: 11.11.2006 01:41 :: hotkid_1 :: Replies: 11 :: Views: 1327
how to calculate DTFT of an analog signal using matlab?
Digital Signal Processing :: 19.12.2006 12:31 :: oualkadi :: Replies: 1 :: Views: 1467
What is the technique to calculate the frequency of an input signal which is at Ghz range.
for example system1's output is given input as sys2. If I want to know the fre of sys1's output what shud be the circuit to be included?
Please help me
And also I want to disply this frequency in an LCD display....
Digital Signal Processing :: 09.01.2007 01:31 :: sivamit :: Replies: 2 :: Views: 573
how i calculate the THD of sample and hold circuits in cadence tool
actually the normal procedure as the select the net and take special function of THD and then plot .
but this is ok with the continuous wave and any amp.
but here the input signal is getting sampled at every clock cycle.
so i need to calculate the THD this regards.
Analog IC Design and Layout :: 15.03.2007 03:03 :: manissri :: Replies: 5 :: Views: 1901
I want to calculate the peiod of this sampling frequency is 369hz?
how can i calculate it's period?
Digital Signal Processing :: 28.09.2007 08:47 :: m_eh_62 :: Replies: 23 :: Views: 8938
I am a little confused: you wrote that you did the processing in time domain but then you wrote that velocity recognition is based on Goertzel algorithm. But this is equivalent to saying that the processing is in Frequency domain, because the Goertzel is a simplified method to calculate fft frequency bins.
Please could you clari
Digital Signal Processing :: 13.10.2007 03:50 :: mowgli :: Replies: 14 :: Views: 9079
i m writing a program in matlab to make the fft analysis of the signal which the user determine
but i dont know how to measure the period of tha signal..
how to calculate the frequency or period of a signal which has two component with different frequencies
plz help meee
Digital Signal Processing :: 01.12.2007 13:33 :: savage67 :: Replies: 3 :: Views: 1987
I want to calculate SNR for sigma-delta modulator.I know that i will require to calculating fft but I don't know that how I can calculate SNR with fft.:cry:
Electromagnetic Design and Simulation :: 31.12.2007 09:02 :: royayeboodan :: Replies: 1 :: Views: 1515
plz help me . refer the following program,
....main aim. i want to generate 2000hz frequncy and plotting time and frequncy spectrum for the same. i have got all the result but frequncy plot result is not correct.
% calculate data
x = sin(2*pi*n1*t) + sin(2*pi*n2*t);
y = fft(x,512);
m = y.*conj(y)/512;
Software Problems, Hints and Reviews :: 20.02.2008 08:47 :: suru :: Replies: 1 :: Views: 691
calculate fft, then plot magnitude response as sqrt(real_part^2+imaginary_part^2). You may consult Matlab help about fft function.
Digital communication :: 02.03.2008 11:54 :: cheggy :: Replies: 5 :: Views: 1352
I appreciate your response about the Hilbert Transform!
When I select that in the Xilinx CORE generator and build it, it gives me the I and Q parts, as you mentioned, the I part is 16 bits , but the Q part is 35 bits. I'm not sure why. It seems, however, that I am able to adjust the output width of Q somewhat based on w
Digital Signal Processing :: 06.03.2008 01:28 :: abort :: Replies: 5 :: Views: 2311
i am doing the final year project about class D amplfier , use some algorithm to produce PWM , then pass to the power amplifier and low pass filter to generate sound.
Since i finish to build the class D amplifier in fypga and also able to see the Power spectral of the generated PWM to measure the THD of the board. The only thing i need to do now
Electronic Elementary Questions :: 15.03.2008 01:00 :: clarken :: Replies: 3 :: Views: 2332
I wondered whether this should be in the DSP section but it involves the Xilinx Core Generator.
After looking at the Core Generator fft module datasheet, I see that the fft core is expecting the data in complex format.
The data I want to transform is from an ADC and will be held in an array, the sampling will be constant rate.
Do I have to
PLD, SPLD, GAL, CPLD, FPGA Design :: 19.03.2008 17:01 :: Rob B :: Replies: 5 :: Views: 1760
I am trying to calculate the cross-spectral density for a voltage signal using Matlab. I am using the fft function to do the Fourier transform. The fft function is Y=fft(X,n). But I donot know how to pick the points n. My voltage signal Y is 2seconds long. dt is 0.0001s. so sampling frequency is 1/0.0001s=10KHz. I donot know (...)
Digital Signal Processing :: 24.03.2008 02:09 :: triquent :: Replies: 4 :: Views: 6476
I had been simulated SDM & calculated fft through MATLAB.
There must be 65536/2 point when you see fft plot between 0~ fs/2 if NP=65536
I think you put your spice output data to MATLAB with the range of 0~fs instead of 0~fs/2.
If i'm wrong, write more.
And I want to know your MATLAB code.
Analog Circuit Design :: 23.04.2008 04:00 :: ljy4468 :: Replies: 1 :: Views: 863
In code composer studio you can use graphs by referring x y axis variables in your code.
1) Set sampling rate of ADC
2) Take samples and copy them into array.
3) calculate fft
4) Use Graph wizards in Code Composer Studio to display.
You can use TI's code support library all three steps. For more information refer help of CSL.
Digital Signal Processing :: 25.11.2010 08:00 :: alperuslu :: Replies: 2 :: Views: 744
how can I define the range of the time-domain random number? Need I to calculate the opamp noise and transfer it to effect of digital output?
Analog Circuit Design :: 23.06.2008 22:40 :: iexplorer :: Replies: 3 :: Views: 841
Hello there, anyone knows how to write a matlab code to calculate the discrete fourier series and its inverse given then verify the code for the following input
Digital Signal Processing :: 04.08.2008 21:07 :: aredhel :: Replies: 4 :: Views: 6357