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audio output error


nolsqn wrote:

hey hi t06afre...can you tell me any way to incease the buffer size ? ..and what do you mean that it is strange code do you know any better way to convert an audio signal to bitstream??

 

thnx


 

The number of samples/ch input value on the Sound Input Configure.vi sets the buffer size


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Message 11 of 20
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hi ...thnx for the help ....but still by increasing or decreasing the buffer siz still the error is ther...i am attaching the vi...plz have a look at it ...thnx for all the help..Error is "a task must be running to perform the operation"..also plz find a sub vi in the code allign array........it is the same vi which comes with the shipping examples of modulation toolkit check the MT OFFSET QPSK TRANSCIVER.vi example .

 

 

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Message 12 of 20
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As I mentioned in my first posting. Your I32_to_bitstream.vi and the rest of the bit stream code was quite "bad" and very time consuming. It gave you some output but the output was wired. Your use of the cast function was not correct at all. The result was buffer overflow for the "sound input.vi"  because the data input was faster than the read rate. In the future I strongly recommend that you brush up your debugging skills. The profile toolbox under tools in the toolbar is also something you should learn to use.  If your code is free of errors, it does not mean that it works as expected ;).

Well anyway Take a look at my solution. I hope my understanding of the term bitstream is correct. As an example the 8 bit 0xb11000010 value translated to a bitstream will give an array equal to 1,1,0,0,0,0,1,0

The bitstream VIs has default values for the input so you can do some standalone testing

Tip By right clicking the sound input/output functions you can select the type for the output

Message Edited by t06afre on 02-26-2009 11:59 AM


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Message 13 of 20
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Well I am not quite perfect as a programmer myself :smileyvery-happy: Then I was working with this last night I selected the "insert into array function" instead of the "replace array subset function" and things started to run very slow. So I had to do some modifications to my plans. Well the result worked but did not executed as fast as I hoped. After looking into the problem once more I spotted the error. And the execution time for the program was as I wanted. The time saving is drastic because the load on the memory manager is reduced. I have attached a PNG showing the result for the profile tool, and the modifications. The "bit stream to 16 bit audio.vi" is unchanged

 



Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
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Message 14 of 20
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hi t06afre...plz look at my attached code ..i am not very good at programming..i didi look at ur vi but when i tired to put mod/demod blk in ur code  it didnt work ..although my attached vi also dont works but it do give me the output for juss a little while until it give the following error plz hav alook at it ...
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Message 15 of 20
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Hey nolsqn,

 

Your latest post is a bit unclear. Did you get the examples t06afre provided to work before making any modifications? How did you try on incorporate mod/demod blk into your code? Did you get any particular errors when you attempted to do this and it 'didn't work?' Also, what errors were you getting when you ran the code you provided in your latest post? Was it the original error you mentioned in your first post?

 

Hope some of these questions help clear some things up.

 

-Ben

Hope this helps.
-Ben

WaterlooLabs
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Message 16 of 20
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what i ment to say that...(if you see the attached vi that i sent) it has mod/demod blk implemented ....when i used the same code in  t06afre  examples it was giving the same problem as mine that is "LabVIEW:  (Hex 0x12D7) A task must be running to perform this operation."......also i didnt send the subvi for my above example sry for that plz find the attached subvi for the above example untitled1.vi
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Message 17 of 20
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Hi your problem is timing again. It take 3.3 seconds to complete one loop of your latest program example, and it takes the sound input buffer 1 second to overflow. I think I can't give you any more help. Because I have zero knowledge in the topic modulation. I think someone else has help you. I guess this is a school project, and your teacher is the nearest person to ask for help. Before you ask him for help you should compile a list. This list should contain topics like what you have done so far, things that are working, things that not work as expected. Also document your debugging results so far. Teachers hate questions like "this program is not working, and I have no idea why. Please help me"

 

Message Edited by t06afre on 02-27-2009 11:10 AM
Message Edited by t06afre on 02-27-2009 11:11 AM
Message Edited by t06afre on 02-27-2009 11:12 AM


Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
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Message 18 of 20
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hi ...dun worry about the modulation juss tell me how to get the timing correct???as you said my complete loop is taking 3.3 sec ..soo shd i incease the buffer size of the sound configure.vi or the sound input read .vi ........ps my teacher doesnt know anything abt labview  ....:-)
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Message 19 of 20
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Ok the bottom line is as follows. You want to do some calculations in "real time" every .5 second. But as your program is now each calculation takes about 3.3 seconds to finish. It is like a dog chasing its own tail. You can not win this one Smiley Very Happy 



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Message 20 of 20
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