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NI 6250 board

I don't understand your question Nyborn.  If you have an FFT that should already be in the frequency domain. 
 
Also, what is a 'beeper' sound.  If you want to do a harmonic analysis of a microphone frequency response, you need to stimulate the mic with a full spectrum.  White noise, swept sine wave, chirps, etc.  A 'beep' would be useless as it only has a small frequency range.
 
Please better explain what you are trying to do.  What is the actual goal of your project.?
 
Regards,
K
LabVIEW Pro Dev & Measurement Studio Pro (VS Pro) 2019 - Unfortunately now moving back to C#, .NET, Python due to forced change to subscription model by NI. 8^{
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Message 21 of 25
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Hi NIquist :

My goal is to use  use a Microphone to detect audio signal so that I  can extract both the frequencies and component levels. I can use these as the criteria for testing whether there is fail or not. I would like to modify the program so that it will only run for certain time if there is nothing acquired, then fail.  This is my goal.

1)First thing I would like to tell you that the Mic output is about 1.5V. This is suitable for DAQ card input voltage. Am I correct?

2) The seond thing is why I need to harmonic analysis to Mic frequecy reponse. If I don't use harmonic analysis, can I just use the frequecncy as the criteria for testing whether there is fail or not. I don't understand here, could you please explain?

Please note that the environment in the manufacturing area contains noise unexpect. I will record my beep sound in a quite enviroment first.

3) Last time, you said don't set 200k/s sampling rate. why? I did not get your meaning. Is that because the PC can not handle that much sample? What is your recommend sampling rate and no of sample

4) You said the beep sound is in low range of frequecy reponse. It wll be useless. Attached is the specification of my mic, the manufacture said it is OK to record when you look at the sensitivity or frequecy reponse. Do you think it is OK to put it in NI CB68LP board and 6250 board. 



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Message 22 of 25
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My goal is to use  use a Microphone to detect audio signal so that I  can extract both the frequencies and component levels. I can use these as the criteria for testing whether there is fail or not. I would like to modify the program so that it will only run for certain time if there is nothing acquired, then fail.  This is my goal.

So you are listening for a beep sound in a noisy environment, if you don't hear it in a certain time, there is a failure.  Is that right?

1)First thing I would like to tell you that the Mic output is about 1.5V. This is suitable for DAQ card input voltage. Am I correct?

The Vs=1.5V in your mic specification means you need to provide 1.5V as a power source.  It looks like you will also need a 1.5 Kohm load resistor across the output.  Then, yes, the output will drive the DAQ.

2) The seond thing is why I need to harmonic analysis to Mic frequecy reponse. If I don't use harmonic analysis, can I just use the frequecncy as the criteria for testing whether there is fail or not. I don't understand here, could you please explain?

If you are just trying to determine if there is a beep at a particular frequency you don't care about the harmonics.

Please note that the environment in the manufacturing area contains noise unexpect. I will record my beep sound in a quite enviroment first.

3) Last time, you said don't set 200k/s sampling rate. why? I did not get your meaning. Is that because the PC can not handle that much sample? What is your recommend sampling rate and no of sample

Your mic can only respond to frequencies below 16KHz.  A 32KHz sample rate is sufficient (Nyquist theorem).  Higher sample rates will not hurt but they will require more computer resources.

4) You said the beep sound is in low range of frequecy reponse. It wll be useless. Attached is the specification of my mic, the manufacture said it is OK to record when you look at the sensitivity or frequecy reponse. Do you think it is OK to put it in NI CB68LP board and 6250 board. 

 I thought you were trying to measure the sound quality of different microphones.  That would require a full spectrum sound source.  If you are only using the beep for a pass/fail test it should be fine.

As far as your microphone, it will work if you get it wired up correctly.  I would still suggest you go to an electronics store and by a small mic and pre-amp that you can simply plug into your DAQ card.

LabVIEW Pro Dev & Measurement Studio Pro (VS Pro) 2019 - Unfortunately now moving back to C#, .NET, Python due to forced change to subscription model by NI. 8^{
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Message 23 of 25
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Hi Nlquist:

 

Hi Niquist:

So you are listening for a beep sound in a noisy environment, if you don't hear it in a certain time, there is a failure.  Is that right?

Yes.

If i test the only beep sound, I can only use frequency reponse. What if I test the beep sound in a manufacturing area with noise this time, how can I detect the beep sound? The frequcncy reponse changes this time. Do you think harmonic analysis can help? The harmonic analysis can only chop the type of sound in certain frequncy. How can I extract the beep sound with noise? Is it because I can use the harmonic analysis to detect the the fundamental frequecy of the beep and then take the fundamental frequency to compare the beep with noise fundametal frequecy to see if the test is pass or not.

An other question is why the component level has four column in the front panel with two of them the same unit. I don't understand why?

Could I use one instead.

 

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Message 24 of 25
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Hi Nyborn,

If i test the only beep sound, I can only use frequency reponse. What if I test the beep sound in a manufacturing area with noise this time, how can I detect the beep sound? The frequcncy reponse changes this time. Do you think harmonic analysis can help? The harmonic analysis can only chop the type of sound in certain frequncy. How can I extract the beep sound with noise? Is it because I can use the harmonic analysis to detect the the fundamental frequecy of the beep and then take the fundamental frequency to compare the beep with noise fundametal frequecy to see if the test is pass or not.

You should base your test on the detection of the fundamental frequency of the beep UNLESS there is a chance in your environment of something else beeping at the same frequency and 'fooling' your test into passing when it did not hear the real beep.  If this might happen you could use the harmonics of the beep to help avoid false test passes.  However, the beep sound must have harmonics (components).   If it is a pure sine signal it will have no harmonics.  You can measure the beep with your VI and see if it has harmonics.  If it does you can base you Pass/Fail criteria on hearing the fundamental AND the proper harmonic components. 

If the first VI you posted (the one with a Fundamental Frequency of 7.37K) is actually your beeper then there are no harmonic components to detect.  Maybe you could make the beep sound longer (1 second or so) and check for its duration as well as the frequency.  Or add another beeper with a different frequency and look for the two fundamental frequencies occuring at the same time.  It's hard to give more advice without knowing the conditions in your manufacturing area.

An other question is why the component level has four column in the front panel with two of them the same unit. I don't understand why?

Could I use one instead.

There are 13 levels in that array if you make it bigger.  The numbers are very small and don't represent valid harmonics, just noise.  If you are wondering why the (m) suffix is on some of the numbers that means milli (1/1000th).  Right click on a number select Format and Precision and change to Floating Point with 6+ Digits of Precision and the numbers may make more sense to you.

Good Luck, K.

LabVIEW Pro Dev & Measurement Studio Pro (VS Pro) 2019 - Unfortunately now moving back to C#, .NET, Python due to forced change to subscription model by NI. 8^{
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