RMS of the FFT or tip?

Similar Questions

• Why the FFT spectrum gives values of RMS?

  Dear Sir

  I want to get the value of crete to crete on FFT spectrum. But he gives values of RMS. Can you please guide me how can we peak to peak on the FFT spectrum. Attach the vi is for example.

  Kind regards

  Urfee

  Tronoh wrote:

  Dear Sir

  I want to get the value of crete to crete on FFT spectrum. But he gives values of RMS. Can you please guide me how can we peak to peak on the FFT spectrum. Attach the vi is for example.

  Kind regards

  Urfee

  What does it mean to get the value of Ridge Crest of a FFT spectrum?  [I understand getting the value of P - P of the signal ...].  Note that the parameters on the average you attached (which shows mean quadratic value, by the way) refers to the way in which the Spectra will be averagedand RMS is logical (logical) in many cases, but I'm at a loss to understand the average peak-to-peak here...

  BS

• Performance of the FFT

  Hello world

  I have copared the original FFT for LabVIEW and MathScript algorithm execution.

  To do this, I calculated a 128 k TFF 100 times. The necessary calculation by MathScript time

  is 4 - 5 times higher. I used a very simple MathScript code that calculates just the FFT,

  No loops, etc. that were involved. Anyone know a good reason for this? It cannot be explained

  through the exchange of data between LabView and MathScript. MathScript uses a less efficient

  FFT algorith that LabView?

  Thank you

  Ulf

  
  

• frequency of the FFT is not compatible with matlab

  Hi all

  Please find .jpg in the attachment. The signal is generated by a signal generator and collected by datashuttle/3000. Then I use the "FFT module" and "statistical value" to find the position max (frequency). I also downloaded the data and processed by matlab FFT function.  What I find, is that the value of the frequency of dasylab is always slightly less than matlab. For example, when the signal generator gives 10 Hz, the dasylab indicate 9,77 Hz and matlab gives 9.99 Hz I used matlab for years, so I have confidence in it. There must be something wrong with my program or dasylab.  First I have is because of the resolution, so I changed the "statistical values - mode - based block and tick (not quite sure about this) parent block and a value for every 240 blocks, which is also for the sampling of matlab."  Unfortunately, there is no change at all. Can anyone help?

  Thank you very much

  Alan

  What is your size of rate and sample block DASYLab?

  Try to make the block size an even number, for example, if you sample at 1000 Hz, made the size of the block 500 or 1000.

  What is the equivalent block Matlab? The amount of data is used for the calculations.

  You can also use the module block average average more than 250 blocks and then use the module of statistical values to calculate the maximum Position.

• What does not restart in the FFT functions way?

  Hi all

  I would like to know what that "restart average" made for the FFT functions. According to aid,"reboot on average indicates if the VI restarts the process chosen medium." If restart on average is set to TRUE, the restart of the VI the selected with an average of process. If reboot on average is set to FALSE, the VI does not restart the process chosen sprawl. The default value is FALSE. When you call this VI for the first time, the averaging process restarts automatically. A typical case when you need to reboot on average is when a major change of entry occurs in the middle of the averaging process"

  I realized that the FFT function takes in an array of values and perform the FFT on it. If the FFT function keep a buffer previous values and clears when restart average = true? Because the FFT functions are not Point by point and they take both in all the data to deal with, "a major change of entry occurs in the middle of the averaging process" can be true?

  Thank you!

  Sigh.  I really tried to explain what was going on (probably) with this function, you use (and, I thought naively, you understand), but you got me wrong.

  

  This VI creates a zero average noise signal, providing 1024 points per second.  Do you know what should be the power spectrum of the signal?  Due to the randomness of the input signal, the power (for a small finished sample) spectrum will also have a random component.  If you had several ghosts of power on average, the average would begin to converge with the expected for random noise power spectrum.

  If you run this VI and look at the Spectra resulting (on average), you will notice that the first spectrum is the most "spice" and that spectra are averaged, the variation is reduced and diminishes the value of crete (shown by looking at the scale of Amplitude).  At any time, you can press "Reset average" and see this... reset the average, the following spectrum shows the growing nose, etc.

  It shows the right way to test the function of the power spectrum and discover what he does. My suggestion as to what makes this function seems to be largely correct.

  Bob Schor

• The size of the FFT unexpectedly affecting maximum frequency

  I was playing around with the Labview Signal Processing course manual exercises (NOR, 1997), when I came across the unexpected result.   I have included below the block diagram for exercise 3.1 (one side FFT) of the manual.  This demo vi had left the size of the FFT (by default).  I don't know what is this default value.  It is not stated in the context-sensitive help.  I tried to add to the size of the FFT.  Unfortunately the FFT analysis did not give a precise answer, when I put in the size of the FFT.  For example, I set the frequency of the 100 s, Fs 300 Hz sinewave and non of the sine wave 500 samples.  When the FFT size has been set to 256, I get 2 to 51 and 102 Hz frequency peaks.  The size of the FFT of 512, I get a peak at 102 Hz.  1024 of the FFT size, I get a polymorphic waveform!

  However when I put the size of the FFT-1 so I got the correct peak at 100 Hz.  I guess that's the default size FFT.  I could also get the correct TFF frequency, if I set the size of the FFT (500) to the same value with # no samples (500).

  Is there anyway I could set the FFT size and still get the correct output of the FFT.  Thank you.

  This was recorded for 2011.

• How to get the fft for my xy graph?

  Hi, I'm Jean,

  I traced xy graphic for an excel file.

  I converted excel file in text file and saved as a .lvm file. now I need to find the fft for this xy graph.

  I will attach my text files and my vi.

  Please, someone put the program and send me quickly.

  I need urgent...

  Here is a simple way to resample the data for a linear ramp of x and make the power spectrum. Modify if needed. (LabVIEW 2011)

  (Fortunately you don't need to worry about the artifacts because each spectral component contains a whole number of cycles in your data)

• How can I extract the frequency of the FFT function?

  Hi all

  How can I extract the frequency of the FFT function in labview?  Thanks in advance

  Concerning

  If you have the f0 and df, you can find your frequency as you would find the time with a waveform based on t0 and dt.  You just need the index of the data point in that you want to get the frequency.  The frequency is then f0 + x * FD, where x is the index of the data point you are interested in.

• How to perform the FFT on medium thanks to the accelerometer is correct or not?

  Hello

  I do FFT on medium thanks to the accelerometer, but display is not correct? Can someone help me solve this problem. I use PKI accelerometer and connecting to NI WSN NŒUD 3202.

  

  

  What is the purpose of feeding one of the TFF to a chart with each iteration of the loop? You have found the spectral components different FFT of different sets of data. The graph of the whole picture emerging from the FFT.

  Lynn

• Amplitude of the Signal after the FFT analysis

  I'm currently trying to find the amplitude of a signal after running a FFT analysis. I use this for image analysis MTF. I take the profile of the line of fire (with an alternation of black and white bars) and convert it to a signal. This signal is then introduced to a FFT Mag/Phase VI extent and output of the FFT. My program then enter the amplitude to frequency of alternating black and white bars.

  My problem is that the amplitude seems to be scaling by a factor. I would like to find the exact amplitude of the signal of my analysis. Anyone know the factor of scale or any problem with my program? I joined the program and the image that must be analyzed. Just browse to the image in the VI and run the program and you will see the MTF chart resulting.

  Thank you

  Ronak

  
  

• How to stop the pop-up tip help Mozilla

  If the update added a few features which I love but a serious makes me angry because I don't know how to stop it. Mozilla keeps offering suggestions on how use the web with annoying help tip popups blocking my screen. He says things like "press Ctrl + W to close tabs. It is faster' and ' to start private browsing...'

  It is SO annoying and I can't find a way to stop it. This isn't the first time I used Firefox and I don't need to be told how to use it as if it was my first time. Help, please... I don't want to go to Chrome. x.x

  It is being run by Mozilla experience. That's because at some point you have installed the test pilot add-on or used a beta version of Firefox and in doing so registered to help Mozilla to test the new features.

  If you want to remove it, feel free to uninstall the test pilot and the add-on experience. Disable or remove modules

• Downloaded Firefox 4 after the pop-up tips. Get same pop up. Firefox 4 is obviously not downloading

  Yahoo toolbar got adivice download Firefox 4. Did this and saved the file. Whenever I log in I get the same pop up tips. It seems that Firefox 4 is not download on my system.

  Try to update via help | Look for the updates.

• HP 15 J8X12UA #ABA: what is the size of tip for the power adapter for laptop HP 15

  Can anyone provide the specifications for the tip of the HP 15 laptop power adapter? I'm looking for more details on the size.

  Thank you.

  Bill

  Reference number:

  45 W HP Smart AC adapter (NFPC, RC, 3-wire, 4.5 mm) 741727-001. 19.5V 2.31 HAS 45W

  Here is a picture with the dimensions of the cutting edge. If it's 'the Answer' please click on 'Accept as Solution' to help others find it.

  

• Cannot write the FFT of the integrated double data

  I am a beginner to Labview environment.
  I have acceleration Vs time dat file .lvm
  Can I get the double integration of this
  acceleration data for trip data.
  Can I get FFT of displacement and displayed on the graph.
  Up to this point VI works
  But now if I connect this FFT of moving to 'write the measurement file' then it displays error.
  Please help me... and correct the error...  All I want is two column data, frequency and

  the other of the amplitude of movement.
  I have attached all files
  I ask you to correct the VI please...
  Thanking you!

  The concepts that you'll want to research are"matrices", "indexing of tables", 'automatic indexing', 'cluster' and 'type of waveform data'.

  The loop IN the first VI I sent used the automatic indexation to take each element of a table 1 d of the clusters and perform operations on them separately to convert them to a waveform.  Exit tunnel also uses automatic indexing so that the end result is a table 1 d of waveforms.  I used the loop, so that no matter how many items appear in the table, you get a corresponding number of signals to the "writing on a file of measures."

  In this case, because the output of the FRF is a single cluster (and not an array of clusters), the loop FOR was not necessary.  The VI attached this time takes the output of cluster of FRF and maps the cluster to a single components build the wave function and you get a result of unique waveform.

  I have no sound and Vibe loaded on my computer at the moment, so I can't run your VI and see the result of the integration of the snout to the Cloaca VI.  The output data type is "Table 1 d of waveform" and your indicator and your two FRF can accept only waveforms.  I put a function between integration and the indicator/FRF array index, but if there is more than one waveform in the table, it would be the wrong solution.  My solution corrects the broken wires but throws waveforms 2,3,4... If they exist.

• How to find the ratio between the two frequencies in the fft

  Hi, I'm Jean,

  I need to find the ratio of the frequencies of 1st and 2nd graph fft.

  Already, I received information of this site only. Mr. Alten helped me.

  Now, I have to continue the same problem and need to find the ratio of the frequencies.

  Please someone help me guys...

  I will attach my vi file and the text file.

  John,

  Should you report the frequencies or the report of the amplitudes of the components at these frequencies?

  The Information.vi of your multiple for the Signal Processing, extract > range of measures of waveform should do what you want.

  The frequency resolution is not very good because you have cycles relatively little waveforms (2 ~ for the lower frequency). I added a few zeros to improve resolution, even if a larger sample of data would be better.

  Lynn