How can I use Hartley transform or other transform (except FFT) to measure harmonics?

[victorchoy]

Dear all,

I want to use the transforms rather than FFT to measure harmonics. I want to use Hartley transform. How can I show the order of harmonics? or are there any other transforms can used to measure harmonics? Thanks.

Victor

[Vivek_N]

Hello Victor,

If you have the Full or Professional Development System of LabVIEW, you can use the FHT VI to comput the fast hartley transform of an input sequence. To see a list of other Transform VIs that are shipped with LabVIEW, you can refer to the following knowledgebase article: http://zone.ni.com/reference/en-XX/help/371361F-01/lvanls/transforms_vis/ . 

[Vivek_N]

Correction. That was not a knowledgebase article. I meant LabVIEW Help :-).

[victorchoy]

Hi Vivek Nath,

Thanks for you help. I have already find Hartley transform on VI. But I don't konw how to show the harmonics which in the waveform. Can you show me some examples of using Hartley transform to show the harmonics? Thanks.

Victor

[Darin.K]

A little curious what you have against the good-old FFT, but the Hartley transform gives you peaks in frequency space just like the FFT.  Be careful that the length of your input is a factor of 2.  

For a chuckle you should check out the Hartley VI example.

labview\examples\viserver\plugin\Hartley.vi

If there is a more useful and informative example that ships with LV I'd like to see it.   

[victorchoy]

Hi Darin,

Thanks a lot. But I still have one question. How can I show the harmonics after I have done the Hartley transform?

Victor

[Coq_Rouge]

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victorchoy wrote:

Hi Darin,

Thanks a lot. But I still have one question. How can I show the harmonics after I have done the Hartley transform?

Victor

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Hi Victor

You can not just sit on chair and hope that somebody just hand over a turn key ready solution. You have to put in some effort your self. You should start by explaining what you want to do much better. Perhaps include some pictures. Because I have not a clue what your problem is

[victorchoy]

My question is that I can use FFT with power spectrum to show which harmonics order contained in the circuit. But if I use Hartley transform or other transform, how can I show the order of harmonics contain? I have use the same method with FFT to plot the power spectrum. But how can I read the correct harmonics order?

[Coq_Rouge]

Sorry but I still do not understand your problem. Can you post your solution that use the FFT analysis

[victorchoy]

The graph below is the voltage waveform of my circuit.

After FFT, I can find out the power spectrum.

This is the way I found the orders of harmonics in my circuit. Now I want to use  another transform to compare the result of FFT. But after I used Hartley transform, I don't know how to show the harmonics.