getting complex waveform from 1d array data??as

[nauman2558]

sir now i have to demodulate this complex waveform which has "0" complex part(it shouldn't be zero). this cmplx waveform must be same as which is transmitted. this all is shown in the above post. thanx sir ur replys are source of great help to me

[GovBob]

nauman,

 Since I don't have your hardware I don't know what your data coming from your DATX 1Chan N Sample is. I assumed you were talking about BPSK which is why I interleaved 0's into the data using the array size, initialize array and interleave array functions. If you remove those functions and wire your data directly into the cast function do you get what you expect? Could you save a portion of your raw data coming from your DATX.vi to a txt file so I could look at it? The DATX.vi is a polynomial function so what other selections are available? I noticed from the png of your front panels that the transmitter has a dt of 62.50E-6 which you need to match with your receiver dt.

[nauman2558]

sir thankyou very much for my help so far. sir i have removed those initialize and interleave functions and now getting both real and imaginary parts. yes sir, you are right i have to get dt=62.50E-6 at receiver too. and sir i am trying to do 4psk. its constellation diagram is shown in the transmitter part. i am attatching 3 png. please have a look at them.

[GovBob]

nauman,

 If you compare the y transmitter data with the y receiver data do they somewhat match. Just visually compare the arrays. I'm guessing you should see 4 values of -0.707 -0.707i, -0.707 +0.707i, +0.707 -0.707i and +0.707 +0.707i but not in that particular order.

  I mistyped my last message when I wrote 'polynomial' I meant 'polymorphic'.

 How fast are you sampling the recieve data? You are transmitter is sampling at 16 kHz so try to match that to see if it helps.

 The Baseband Developers Toolkit is a good resource to understand I and Q.

[nauman2558]

yes sir, you are right i am getting all these four combinations( in complex input data). i am transmitting and receiving both at 16000 samples per second. thank you sir, i just took a look into it, it will really help. i will study all that in the evening. and plz tell me to get my dt as transmitted.

regards

[nauman2558]

and my samples per channel are 2000

[nauman2558]

sir i have read all that baseband developers kit resource but still not able to get dt from the waveform 😞 . please help sir. dt, which is the time difference  between y points, is it possible in labview to measure that time?

[GovBob]

nauman,

 dt is indeed the time between samples. In your application what determines the time between samples? Perhaps the sampling rate?

[nauman2558]

sir, i am confused how dt=sampling rate? at my transmitter the sampling rate is 16000. while its showing dt=62.50E-6. and at receiver part i am getting -0.707 -0.707 i or +0.707 +0.707 i. not +- and -+ combinations. plz help me out.  i am sending you png of transmitted complex waveform and receved data too. and also the block diag of how i am converting read 1D data to complex waveform. please have a look at them.

[nauman2558]

sir i am sending you another png with some changes in receiving part but getting almost the same results. please have a look at it.