LabView

[sine_help]

hello

i want to know that signal generated by simulate signal is complex or real. i have a QPSK signal in which a symbol has 16 sample.how to find phase of symbol

[parthabe]

Signal generated by Simulate Signal Express VI is Real Double.

Use the Extract Single Tone Information.vi from the Waveform Measurements pallette to measure the Phase of the signal.

[sine_help]

Thnks for answer   but  i want to generate complex sin wave( in terms of x+iy) in labview .

[parthabe]

Sine is a real-world signal.

Why do you want it to be complex? Where do you apply it or find its use?

[sine_help]

i have a QPSK signal which is generated by matlab simulink . for modulation i have use sine wave ( complex properties) . i have make a wav file for that signal . when i read it in labview  it gives real and imaginary values . now i want sine wave with complex properties to demodulate it as in matlab.

[stanthetiger]

If I remember correctly, the real and imaginary part of a signal is just a different way of conveying amplitude and phase of the signal. The magnitude of the signal is equal to sqrt(Im^2+Re^2). The phase of the signal is equal to InvTan(Im/Re).

QPSK modulation scheme uses the phase difference to convey information. By shifting the signal π / 4, 3π / 4, 5π / 4 and 7π / 4, we can represent 2 binary bits of data.

All you need to do is calcuate the manitude and phase of the signal, then you can use the Simulate Signal Express VI to generate the signal you want.

Regards,
Stanley Hu
National Instruments
Applications Engineering
http://www.ni.com/support

[sine_help]

i have generated a cos wave of frequency 50Hz. i want to convert it into sine through hilbert transform but when convert it frequecy of signal become .00625 Hz  Please tell me why this happen and how to remove this effect.

[stanthetiger]

Hi sine help,

What VIs are you using? Can you post a simple VI that illustrates the issue?

Regards,
Stanley Hu
National Instruments
Applications Engineering
http://www.ni.com/support

[smercurio_fc]

Hmmm.... This seems oddly familiar, even down to the title of the thread....

[sine_help]

Please check this and tell me why frequency charges from 50Hz to .0065Hz