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Cross Correlation of two sound signals 
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#1
Jan213, 01:04 AM

P: 1

Hello!
We are trying to verify if an acoustic standing wave has been established in a cavity. In order to do so, we are giving a constant frequency signal to a speaker. We are picking up the signal at two locations, one very close to the speaker(reference signal) and at a particular location(captured signal). We are cross correlating them. Ideally, we are supposed to get a zero phase difference between the two signals for the frequency sent in, proving that the reference and captured signals are varying simultaneously in time. However, we are getting a jump from pi to pi at that frequency ?(here,its 520Hz). Could anyone explain what is happening? Thank you for taking your time for this! 


#2
Jan313, 06:45 PM

Mentor
P: 40,730

Could you also post a diagram of your cavity, showing the speaker location and the locations of the microphones? 


#3
Jan313, 09:16 PM

Engineering
Sci Advisor
HW Helper
Thanks
P: 6,962

Also, what are you measuring (or calculating) on the plot that looks like an amplitude? The sudden change in phase suggests the system has a mode (or resonance) at that frequency, but without a drawing of the complete setup it's hard to guess what is happening. 


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