Générer une implusion avec "Sine Wave Generator" en FPGA

Bonjour,
Content de vous rejoindre sur ce forum. Tout nouveau en Labview (pas très à l'aise avec certaines notions), je voudrai soliciter votre aide. En fait, je veux créer une impulsion de 100Hz avec la fonction " Sine Wave Generator" de FPGA. En simulation j'ai réussi mais dès que je compile en target il m'affiche ce message : "Top-level clock rate does not match rate for which the Sine Wave Generator VI was configured. Reconfigure the Sine Wave Generator or the top-level clock so that their rates match. You also might need to modify computed values for the frequency (cycles/tick) input."
Je change donc FPGA clock rate et je choisis 40MHz (la seule qu'il me propose). Mais dans ce cas, je me perds pour retouver mon impulsion (qui doit durer une période 0.01sec). J'ai essayé de jouer sur le nombre d'échantillons en changeant le nombre d'itérations de la boucle For afin de générer toujours une période ( pièces jointes) mais ça marche pas!!!
Pourriez vous m'aider à déchiffrer ce problème?
Merci d'avance
Pièces jointes :
burst sine.png ‏372 KB
burst sine_40MHz.png ‏336 KB

Bonjour M2IM,
En mode simulation, on utilise une fonctionnalité appelée "Interactive Execution" car l'exeuction/affichage ne peut être géré à une fréquence élévé (40 MHz dans le cas de la Top Level Clock par défaut).
En mode FPGA target, la vitesse est plus élevé et donc uniquement certains points du sinus seront afficher mais le signal electrique lui sera bien un sinus.
Je t'invite à regarder le lien ci-dessous qui reprend quasiment la problématique que tu rencontres:
Generate a sine with LabView FPGA and connect it to an AOModule
Bonne journée,
Valentin
Certified TestStand Architect
Certified LabVIEW Developer
National Instruments France
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FPGA sine wave generator

NI工程師你好
我在FPGA端使用sine wave generator
可是出來的波形卻不是一個完整的Sin波圖形
可以請工程師幫我解答一下嗎??
已解決！
轉到解決方案。
附件:
sin.png ‏10 KB
sin-1.png ‏13 KB

好吧，我認為問題可能是您使用的圖表上的FPGA。不幸的是，LabVIEW的通信方式，有時會導致與 FPGA圖表更新不當，因為他們目前沒有時間同步的時間在芯片上。我組建了一個簡單的應用程序，而不是傳輸分回的主機和波形似乎是正確的。讓我知道這是否有助於。
附件:
Sine.zip ‏317 KB

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Luc Desruelle | Voir mon profil | LabVIEW Code & blog
Co-auteur livre LabVIEW : Programmation et applications
CLA : Certified LabVIEW Architect / Certifié Architecte LabVIEW
CLD : Certified LabVIEW Developer / Certifié Développeur LabVIEW

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je voudrais récupérer une sauvegarde du mois d'aout 2012 mais il ne m'apparait plus qu'un suavegarde faite aujourd'hui .
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Although many topics of simultaneous analog output and input can be found in NI Developer Zone, I have not found a case similar to my project. I'm trying to generate a 1kHz sine wave by using the analog output of NI DAQPad-6070E, and acquire one channel input signal simultaneously. I found most of the examples can not work properly above 100Hz. Any suggestions are welcome. Thank you.
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On Tue, 3 Feb 2004 09:03:07 -0600 (CST), jujian wrote:
>Although many topics of simultaneous analog output and input can be
>found in NI Developer Zone, I have not found a case similar to my
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>
>Jian

Unable to generate sine wave

Hello everyone!
I am currently working on my Bachelor project at a company. i am stuck with a problem.
I have designed a labview program for vibration test system. I have used cRIO 9076 as the controller with NI 9263(as D/A) and NI 9234(as A/D).
The loop works as follows. the input is given from the labview program. it is then sent to the cRIO. the output of CRIO(that is output from NI 9263) is given to the amplifier. the vibration shaker vibrates based on the input from aamplifier. then the accelerometer detects the vibration and sends it to the NI 9234 and loop repeats iteratively. since i have designed a sweep sine vibration system, the output of cRIO is a square wave. it should be sine wave.
the probelm is i am getting a square wave as output from my NI 9263 which should be a sine wave output. I have two subVI where i use nominal to binary convertor(for NI 9234) and binary to nominal (for NI 9263) as calibration mechanism.
the question is where have i went wrong? what should I do to get a sine wave?
PS: on searching NI i found out some formulas (to generate sine wave) and designed a FPGA and LabVIEW program to generate a simple sine wave and got a sine wave. if that formulas is to be included where should i include that?
Thanks in advance.
Regards,
Vishal.

Without seeing your current code, there is no way we can even uess as to why you are creating a square wave instead of a sine wave.

How to measure time difference between zero crossing of a sine wave and rise time of a pulse on a same graph?

I have a 50Hz sine wave and a pulse signal on a same graph. The phase difference between two is between 0-90 degrees.
Now I need to calculate the time difference between (when the sine wave crosses zero volts) and (when the pulse rises). The frequency will stay approximately same for both signals.
The application is for a three phase generator. In simple words, when the time difference between the zero-crossing of sine wave and the pulse rises increases, that means that the load on the generator has increases.
I am a beginner user of LabView (version 9, 2009), maybe it is a very simple problem but I've been pulling my hair out for the last few days and coudln't figure anything out. Any help would be greatly appreciated. I am using DAQ USB-6008 to measure these voltages and pulse from the generator and a sensor
I have attached a jpg (a graph that i just made with excel to explain). The time 't' is what I am trying to measure
Cheers
Awais
Message Edited by awais.h on 03-30-2010 11:20 PM
Message Edited by awais.h on 03-30-2010 11:21 PM
Solved!
Go to Solution.

Hi
Thanks for the code but I'm afraid it won't work. Like you said the probability of choosing a value that is on both graphs may not happen. This is something that I would like the code to do automatically.
But I did use the previous code posted and made some modifications to it and it seems to work perfectly. Now the next thing is to be able to get just that one value that tells you the first time difference.
Here is what I get using that code.
As you can see from the t Values. I only need the one that is highlighted. If there is a way to filter out the rest it would be great.
I was thinking of a while loop and as soon as the value is higher than 3E-5 it would store the number and stop the loop, but I'm not too familiar with arrays in labview.
Here is the the code modified.
As you can see, it wasn't that big of a modification and it still is your code.
I will keep trying.
Thanks for the help
Attachments:
FinalShockSpeed.vi ‏55 KB

Question on the result of using Wavelet transform on sine wave

Dear all,
I have apply the Wavelet transform on a 50Hz sine wave. The result is shown below. But I don't understand the result of Wavelet transform. Anyone can help me? Thanks.
Victor

You seem to have something against the FFT, yet continually compare other transforms to the "sweet spot" for the FFT, ie. sinusoidal and periodic functions. Without trying to write a treatise on the subject (there are many fine books), a few observations.
The primary purpose of any transform pair is to perform a rotation in function space, for the FFT we are familiar with the time domain and frequency domain. The wavelet domain is not so simple. The FFT is very effective for sinusoidal and periodic functions, ie. those that have no localization in the time domain. If you have a sinusoidal input, the infinite signal in the time domain can be reduced to a pair of numbers (one if you take the power spectrum). That is very efficient, other periodic signals can usually be approximated by a small number of terms.
Wavelets on the other hand are chosen to be localized in both the time domain and the wavelet domain. If you look at a periodic signal like your sine wave, you see a mess, and to recreate the input signal you will need to keep an awful lot of the points around for the inverse transform. You may be able to set the last 1/3 to zero, but that's it. To see an effective application, you should be looking at localized functions, like an impulse. Put an impulse into the wavelet transform and you get something that is still a bit complex, but pretty simple. The FFT of an impulse contains components at all frequencies and the wavelet clearly wins in this case.
On paper, there is usually a clear choice, and the FFT almost always wins for spectral estimation. On the other hand, if you are trying to compress "real world" data, for instance an image, then there is a choice to be made. Standard JPEGs are FFT based, you take the FFT and try to keep just the largest frequency components. As you probably notice, edge contrast usually suffers, especially at higher compression. With wavelets, it is typical to have slightly better contrast leading to better preservation of details for a given compression.
In short, my opinion is that transforms are useful when they simplify the problem. Wavelets do not simplify the representation of a sine wave.

Générer une implusion avec "Sine Wave Generator" en FPGA

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