Compare similar shape Waveforms

[sksingla]

Hi,

I want to compare two waveform having same shape and same sampling time but time shifted. I am comparing Y values sample-by-sample in lab view. But due to timing mismatch between two waveform, i am not able to compare similarity between two waveform. Can you please suggest a method how we can do?

Attached is example of waveform.

Thanks,

Sunil Kumar

[PalanivelThiruvenkadam]

No attachment found.

As stated you will see the difference if you compare two waveforms straight within which has time shifted in one waveform.

Do you need to eliminate time shift?

Attach the Developed vi.

[sksingla]

Hi Palanivel,

Please find attached example of waveform. Actually we have multiple waveforms of same shape and have same sampling rate. But due to timing mismatch I am not able to compare waveforms by using point to point Y Value comparison.

Thanks,

Sunil Kumar

[PalanivelThiruvenkadam]

Do you want to eliminate the time shifting?

If yes, Derive a algorithm/ use filtering option to remove the time shift data and compare the exact values where both the waveforms matches each other.

[sksingla]

No, I don't want to ignore time shifting.

Please let me know if you need any more waveforms information.

Thanks,

Sunil Kumar

[Bob_Schor]

Have you studied Signal Analysis?  The first thing you want to do is to determine the magnitude of the Time Shift -- there is a method, called cross-correlation, that will give you a statistical estimate for this.  Once you know the shift, you can do whatever you want with the waveforms.

Before using any analysis technique, I strongly recommend learning the theory behind it, otherwise you will "get answers", but they may be meaningless because you ignored the assumptions and caveats associated with the methods you used.

Bob Schor