Respondida
How to ignore NaN values in pcolor function?
I don't think the black lines are because of the NaNs. Its coming from the default shading method, which is faceted. Try "shad...

más de 7 años hace | 0

| aceptada

Respondida
Efficient method for getting positive half axis only from FFT
If I understand your question, you are getting the answer you want, but you are trying improve the efficiency. If you only care...

más de 7 años hace | 0

| aceptada

Respondida
Nested for loop outputs
I'm not sure if entirely understand the question... why not just do this for the last block? for j = 1000 iterations ...

más de 7 años hace | 0

| aceptada

Respondida
Eigen values differs with mchines
high condition number is not the same thing as non-deterministic. If you repeat an ill-condition computation multiple times, ...

más de 7 años hace | 0

Respondida
indices for zero crossing of a Sine Function
First question: why is there an extra one at end? Because of the way you handled the "missing" point at the end: drvY = [drv...

más de 7 años hace | 0

| aceptada

Respondida
wave phase adjustment between several signals
I think xcorr() may help here. xcorr() will basically try every possible time shift for you, and let you know what shift makes t...

casi 10 años hace | 0

Respondida
FFT don't give correct result
first, "f = Fs*linspace(-.5,.5,length(data));" is not exactly how matlab outputs the frequency vector. To get something like th...

casi 10 años hace | 0

| aceptada

Respondida
FFT analyzing of signal and signal reconstrution. (I want to reconstruct by suming a*sin(w*t-phi)
You forgot the negative frequencies. You didn't state explicitly the definition of simpleamp, but I think length(Simple) should...

casi 10 años hace | 0

Respondida
if the number of samples for doing fft is not n power of 2 the results accuracy would be affected or it is just matter of speed of calculations ?
There are two reasons to zero pad an fft. First reason is speed. A sample size that is a power of two is going to be the faste...

casi 10 años hace | 0

| aceptada

Respondida
how to generate a Sine wave with changable frequency in mfile?
the short answer is that you cannot just multiply f by t to get what you want. You need to integrate f with respect to time to ...

casi 10 años hace | 0

| aceptada

Respondida
how can I recover original frequencies from a data table acquired from osciloscope?
well, fft() function is a good start. I'm guessing if you are asking this, then you don't know much about fft() function. This...

casi 10 años hace | 0

Respondida
Power Spectral Density for HRV, need help with pwelch function.
if your input is in volts, then your output is V^2 / Hz. If your inputs are in some other unit, let's call it X, then your outp...

casi 10 años hace | 0

| aceptada

Respondida
power spectral density of fft
well, in some sense, you can never really "get" the PSD of anything. you can only *estimate* it. And yes, the fft magnitude sq...

casi 10 años hace | 0

| aceptada

Respondida
How do I perform zero phase filtering in Matlab?
First, your line "freq = 0:binHzConv:100;" is not correct. Frequency does not range between 0 and 100 Hz in your example, but r...

casi 10 años hace | 0

| aceptada

Respondida
How to create impulse noise? (e.g. interference in a cable plant)
this reference might be a good start http://dsp-book.narod.ru/305.pdf

casi 10 años hace | 0

Respondida
Need Help with FFT
Here's a little tutorial I wrote that may help get you started. http://www.mechanicalvibration.com/Making_matlab_s_fft_functio.h...

casi 10 años hace | 0

Respondida
How can I differentiate without decreasing the length of a vector?
My standard approach is to use 2nd order centered difference for the main part of the vector, and use first order forward and ba...

alrededor de 10 años hace | 0

Respondida
How to choose the appropriate low pass filter?
if you are new to filtering, and just want a simple low pass filter to remove noise, then start with a butterworth filter. It m...

alrededor de 10 años hace | 0

| aceptada

Respondida
Questions about FFT (and applying it to determine power spectral density)
"Question 1: Why isn't the scaling of ( 2 / numberOFdataPOINTS ) applied within the FFT algorithm." Matlab uses what I like t...

alrededor de 10 años hace | 1

| aceptada

Respondida
FFT accuracy and 'Noise Floor'
Standard double precision floating point arithmetic is good to about 16 significant digits. So trying to do what you are doing ...

alrededor de 10 años hace | 0

| aceptada

Respondida
How can I determine the maximum frequency or bandwidth of a coded audio signal?
Well, on the one hand, for any digitized signal, the maximum frequency that can be represented is half the sampling rate. B...

alrededor de 10 años hace | 0

| aceptada

Respondida
Why is spectrum.periodogram not recommended, and how to substitute pwelch in it's place?
Well, first, is your signal a random variable? Or more of a periodic signal (i.e. a sine wave)? If it's periodic, then just a ...

alrededor de 10 años hace | 1

| aceptada

Respondida
How can I write a function about upsampling in DSP
resample() work might for you to upsample the data. Filtering in matlab is a two step process. First, you have to design the ...

alrededor de 10 años hace | 0

Respondida
convert time from sample to second
Well, if the time step is 0.001s and you have 300 samples, then 300 * 0.001 = 0.3, which is not 10s. So either you don't really...

alrededor de 10 años hace | 0

Respondida
FFT of NMR signal: frequency cut off
Hi Nicolai. I'm not sure exactly what you are expecting to see, but I suspect you just didn't multiply by 2 when converting f...

alrededor de 10 años hace | 0

Respondida
Temporal waveform reconstruction from spectral magnitude only
Without the phase data, it's basically impossible to reconstruct the original time domain signal. Sorry. Cepstrum analysis wil...

alrededor de 10 años hace | 0