Sending an output in LabVIEW to Simulink as an input

[adeel1]

oh thanks for ur reply, i knew the zero pading at the ends but am interested  "in between" the array like [0.707 0 -0.707 0 -0.707...]

and more importantly you didnt tell about my question about idwt, i'll be greatful if you can assist me please...the question was:

let suppose if the we input 4QAM modulated signal let say(0.707+0.707j) into inverse discrete wavelet transform and then use discrete wavelet transform to get back the symbol but after doing it, we only get the real part let say 0.707 not the imaginary part, how can it be resolved ? as in ifft/fft it's working fine

God bless you !

Regards

A.Adeel

[David_A]

Take a look at this link. This is a knowledgebase article that talks about QAM and also gives an example. Take a look at this and see if that sheds any more light on what you are trying to accomplish.

David A.

[adeel1]

Dear you are not getting my point; there is nothing wrong with modulation scheme the problem is in discrete wavelet transforms!!!! Please read the question, I am having problems in reconstruction the signal back, specifically saying QAM but the problem is almost same with every modulation scheme

[Justin__D]

I'm not sure if I completely understand your question.

So you are inputing a QMA signal into the "inverse discrete wavelet transform.vi" and then passing this into "discrete wavelet transform.vi"?

And you are only getting the real part back but are expecting both a real and imaginary part, correct?

Justin D.

[adeel1]

ya exactly but input to a "inverse discrete wavelet transform"  and one more thing how to give delay(Z^-n) in labview ??

thanks

Regards

A.Adeel

[MorganS]

Hi Ahsan,

I created a small VI that replicates the issue you've described.  You can see the coercion dot on the Discrete Wavelet Transform VI - it is being converted there from a complex waveform data type to just a waveform (the imaginary part is being dropped).  This would indicate that the VI does not accept complex waveforms, but I'm not sure what the best workaround would be.  Can you confirm that this is the problem you're seeing as well?  Also, can you give some more detail about the delay you mentioned?

Thanks,

Morgan S

Applications Engineer

National Instruments

[adeel1]

• thanks a lot, i appreciate your effort, i have sent you a doc file to give you an idea of how it looks.

idwt/dwt does except complex symbol but drops the imaginary part by default. if you try to separate the both or try what i did than still useless.

have a look and than tell me

• the delay i was talikng about is the one we use in simulink just to delay a signal N sample periods(integer delay)

• another question i asked before and no one replied me was....how to pad zeroes in between the samples like [0.707  0   0.707   0    -0.707]

[Patricia B]

Hello,

Attached is a snippet of a vi that should pad an array with zeros as you described. As for you first question, would you mind posting a sample of the arrays you have and the arrays you want.

Regards,

[adeel1]

Hi thanks

I have done it by simply using the upsampler with some speified parameters...

now i am having very annoying problem..there are two things to be implemented in labview they are:

1. how can we implement the ostbc combiner in labview ? do we have any block as we have in simulink
2. how to interpolate data as it is interpolated in the simulink block with name interpolation ??

please reply soon am traped badly, i have tried many things but fed up !!

Regards

A.Adeel

[Brian_A]

Hi 

1. I'm not sure what function the ostbc combiner performs as I could not find info on it. Do you mind posting documentation on what it does?

2. There is Interpolate 1D Array under the array pallet and another set of Interpolate 1D and 2D array interpolation nodes included in the G Math toolkit

<Brian A | Applications Engineering | National Instruments>