How is calculated the amplitude in the FFT function?

Hello,
I have a time signal, for example an 1KHz tone. I use the FFT complex function to calculate its Fourier Transform, and I want to Know, which is the relation beetween the amplitude of this FFT and my time signal.
I have an example of a sine of 1KHz with an amplitude of 1V. When I calculate the FFT the result is one delta at the correspondient frecuency, but with an amplitude of 12149. My signal has 65536 samples.
Could you help me please?

With the complex FFT, I do believe you have to normalize the by half the size of your sample set. This should give you back the original magnitude of your signal. Take a look at this screenshot.
Attachments:
fft_magnitude.jpg ‏65 KB

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Adjust the frequency and the amplitude of the harmonic

hello all
I have a program that works but I want to know how do you adjust the frequency and amplitude of harmonics,
please find attached my program
thank you in advance
Attachments:
program.vi ‏41 KB

Hi Cherifalami,
With your VI it could be possible configure the amplitude and frequency of your harmonics directly through the equation you input to the f(t) generation VI.
Here is an additionnal code you could use to simulated a mutliple harmonics signal.
Best regards
Romain DUVAL || Application Engineer Specialist ||Certified LabVIEW Architect (CLA) || Certified TestStand Architect (CTA)
National Instruments France
Attachments:
exemple.vi ‏25 KB

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To increase the amplitude of a spectrum

hello,
I have a spectrum and I would like to increase the amplitudes of the fundamental frequency and harmoniques. Is it possible ???
Thank you ?

Hi,
When using "Harmonic distortion analyzer.vi" you can get the fundamental frequency and its multiples in array.
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Attachments:
Increase Harmonics.vi ‏97 KB

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Hi Hillary,
Thanks for your reply.
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How do I use the context of the column as part of my calculated measure/column?

Hello,
I've struggled with this for a week now.
I need my calculation to take the context of the column that it's in and use that value as part of a lookup/filter with which to do an operation.
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pseudo-code would be:
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Kind Regards,
Alex
Link to the XLS on onedrive
_https://onedrive.live.com/redir?resid=67E698690736D027!3358&authkey=!ADU5F41Sg08Ygm0&ithint=file%2cxlsx
Link to image showing data and what the pivot answer should look like _http://i.imgur.com/2HC7Lk7.png
Link to image showing the data model _http://i.imgur.com/KK3b61v.png
(I'm waiting to be verified..)

Yes, you're right, my calculation first attempt only works if the ORU and MGR are on the rows. :(
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How do I create a 1d array that takes a single calculation and insert the result into the first row and then the next calculation the next time the loop passes that point and puts the results in thsecond row and so on until the loop is exited.

The attached file is work inprogress, with some dummy data sp that I can test it out without having to connect to equipment.
The second tab is the one that I am having the problem with. the output array from the replace element appears to be starting at the index position of 1 rather than 0 but that is ok it is still show that the new data is placed in incrementing element locations. However the main array that I am trying to build that is suppose to take each new calculation and place it in the next index(row) does not ap
pear to be working or at least I am not getting any indication on the inidcator.
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Attachments:
regulation_tester_7_loops.vi ‏244 KB

I didn't really have time to dig in and understand your program in depth,
but I have a few tips for you that might things a bit easier:
- You use local variables excessively which really complicates things. Try
not to use them and it will make your life easier.
- If you flowchart the design (very similar to a dataflow diagram, keep in
mind!) you want to gather data, calculate a value from that data, store the
calculation in an array, and loop while the time is in a certain range. So
theres really not much need for a sequence as long as you get rid of the
local variables (sequences also complicate things)
- You loop again if timepassed+1 is still less than some constant. Rather
than messing with locals it seems so much easier to use a shiftregister (if
absolutely necessary) or in this case base it upon the number of iterations
of the loop. In this case it looks like "time passed" is the same thing as
the number of loop iterations, but I didn't check closely. There's an i
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- After having simplified your design by eliminating unnecessary sequence
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Don't try to use the "insert into array" vis since theres no need. Each
iteration of your loop calculates a number which goes into the next position
of the array right? Pass your result outside the loop, and enable indexing
on the terminal so Labview automatically generates the array for you. If
your calculation is a function of previous data, then use a shift register
to keep previous values around.
I wish you luck. Post again if you have any questions. Without a more
detailed understanding of your task at hand it's kind of hard to post actual
code suggestions for you.
-joey
"nelsons" wrote in message
news:[email protected]...
> how do I create a 1d array that takes a single calculation and insert
> the result into the first row and then the next calculation the next
> time the loop passes that point and puts the results in thsecond row
> and so on until the loop is exited.
>
> The attached file is work inprogress, with some dummy data sp that I
> can test it out without having to connect to equipment.
> The second tab is the one that I am having the problem with. the
> output array from the replace element appears to be starting at the
> index position of 1 rather than 0 but that is ok it is still show that
> the new data is placed in incrementing element locations. However the
> main array that I am trying to build that is suppose to take each new
> calculation and place it in the next index(row) does not appear to be
> working or at least I am not getting any indication on the inidcator.
>
> Basically what I am attempting to do is is gather some pulses from
> adevice for a minute, place the results for a calculation, so that it
> displays then do the same again the next minute, but put these result
> in the next row and so on until the specifiied time has expired and
> the loop exits. I need to have all results displayed and keep building
> the array(display until, the end of the test)Eventually I will have to
> include a min max section that displays the min and max values
> calculated, but that should be easy with the min max function.Actually
> I thought this should have been easy but, I gues I can not see the
> forest through the trees. Can any one help to slear this up for me.

I am using Numbers on my iPhone5 and cannot get the app to do a simple (SUM) calculation. It shows the formula correctly in the cell, but all I get for my long list of numbers to add is 0. How can I get this to work?

I am using Numbers on my iPhone5 and cannot get the app to do a simple (SUM) calculation. It shows the formula correctly in the cell, but all I get for my long list of numbers to add is 0. How can I get this to work?

Oaky, at least we got that far. Next step is to determine if all those "numbers" are really numbers. Changing the format to "number" doesn't necessarily change the string to a number. The string has to be in the form of a number. Some may appear to you and me as numbers but will not turn into "numbers" when you change the formatting from Text to Number. Unless you've manually formatted the cells to be right justified, one way to tell if it is text or a number is the justification. Text will be justified to the left, numbers will be justified to the right.
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+123
123 with a space after it.
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Hi All,
I have a scenario like this :
Look into the follwing Data.
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.........so on
The workcenter is different is two blocks of example data, and hence to be calculated differently.
Now how to achive this,
I appriciate your insite on this problem.
Regards
Shaan.

Hi Philips,
Thanks for your response.
I want to make you more clear about the problem.
We are calculating based on the following combinations.
PLANT--RUNDATE-WORKCENTER-SHIFT-----PRODUCTTYPE
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Rundate is assume as the Calday.
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Now i want to insert a new column in the CUBE and wanted to have the TOTAL ALLOWED TIME in every line item,
might not seem to be a good idea, but just let me know how to do it.
If it is not clear, you can ask me for further questions.
THANK YOU PHILIPS.
Regards
Shaan

How does one increase the y-axis (amplitude) of the audio tracks?

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DrDtMM
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How is calculated the amplitude in the FFT function?

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