( active noise control using loudspeaker )

[johnsold]

Please try to use complete words such as "you" rather than "u". For many of the people who use these Forums English is not their primary language and the use of shortened forms makes it hard to understand.

Consider the steps which must be performed.

-The program must acquire a signal from the microphone.

-It must analyze that signal to determine the frequency, phase, and amplitude of the  largest component.

-It must generate a new signal at that frequency and determine the appropriate phase and amplitude to produce cancellation.

-It must send that new signal to the DAQ AO line.

Now determine which parts of my program perform those tasks or simulations of them. Replace those parts with the code which uses the real signals. Modify the program control structure to work with real signals.

For example you have a VI which obtains a signal from the Sound In port of your computer.  That corresponds to the Tones and Noise.vi connected to Sine phase 0 in my program.  You may also need to change the timing as I discussed earlier.  I suggest starting with segments of 0.5 to 1 second and then make chages as needed.

Try this process and see how far you can get.

Lynn

[ALI2020]

Hello Lynn
thank you very much and I apologize for the short form I have used as I am new and next time I willnot do that for the benefit to others ..
Actually Lynn I found  program from internet which can do my project as now I have no time and I have tried but I am quite sure all my theory that I have implemented and no point achieved so hope if you can analyze the file attached and tell me why input and output data are missing file or have been moved ?
Please Lynn this will help me a lot 
thanks 
regards 

[NIquist]

The file you're looking for will be different for every microphone/speaker combination.  It represents the audio path between them so it is required for the code to work properly.  However, even if you could generate that file you will still need a fast, real-time PC to actually do ANC (as Lynn has already mentioned).

Sorry to say it but I think you may be attempting a project that is beyond your skills and resources.  Perhaps there's a way to try something a little simpler?

Also being handled here:  http://forums.ni.com/t5/LabVIEW/Enquiry-about-missing-file-in-program-attached/td-p/2680287/highligh...

[ALI2020]

hello NIquist
thanks 
 "I think you may be attempting a project that is beyond your skills and resources" this is totaly true and i know it basically labview and its functions needs time and beside that sound properties and the interfacing and detecting beside the elemination of delay is beyond my knowledge which i cannot do this withing three months and i have faced many problems regarding labview labraries and i spent time learning labview but i still consider as beginer ... my plan was to get the code to help me analyze it , understand and then be able to achieve my project as labview coding isnot in my major and i wish if i have time to do anything >>>> thanks all 

[NIquist]

Well again, perhaps there is a simpler application that you could try like showing why the real-time cancellation of one sound signal by another is so difficult when you must deal with the physical properties of acoustics and the limitations of computers.  There is a reason that all the noise cancellation products on the market are based on headphones.  Headphones minimize the variables like the audio path and reflections and allow a small, fast processor inside to do the math in real-time.

Your idea was very sound.  Don't put it aside completely.  Just look for a project that is within your resources and push ahead.  Learning LabVIEW takes time but there's no better way than creating a project that interests you to make the learning fun.  Good luck and post back if you need further help...

[ALI2020]

 hello NIquist
firstly thank you very much based on your advices i should look back for resources help me understand it this is for future analysis and study for the time being as student and don't have that much knowledge I was trying how to implement based on any code whoever make it as I tried days but no point ...
I hope if can do it and then if I have any enquiry I can post it back 
really I appreciate all your help your guides and your valuable advices as expert .....
Regards 

[ALI2020]

 hello NIquist
i have just basic questions and i need to learn such things hope you can answer me 

how can i know the exact delay between input and output signal ? is there such function in labview ? i have used co and crossrealtion but alawys give me the same value even if i changed and also repeated thing in 100 ms ...
is there such function in labview can do phase shifting ?
what is the meaning of output array basically ? 

[NIquist]

Stick with the time domain if you want to measure time.  There's no reason to mess with phase.  Just record a sharp noise like a hand clap or a digital pulse and measure the delay by subtracting the timestamps.

[ALI2020]

Hello NIquist
thanks a lot for your answer am trying to do small experiment first to understand more and read resources then if i face any problem i can highlight here thank you very much 


regards 

[ALI2020]

Hello everyone 
hope you can help me by seeing my file and tell me what is the things that is not needed I am trying to get signal and take this signal parameters and send it to the daq (that is connected to amplified speaker  ) with phase shift 180 so it can cancel out the signal acquired but when I implement this in lab I couldn't get the result expected can you please help me figure it out >>> sorry to all of you I,m not expert in this field ..... Thank you very much