LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

real and imaginary part

How to extract real and imaginary part from dynamic data? I tried it using integral vi, but i don't know how to multiply signal by sin and cos in correct phasecode.JPG?

 

this blue blocks are vi from microdaq lite

0 Kudos
Message 1 of 9
(4,146 Views)

Which wire do you think contains complex data? 

0 Kudos
Message 2 of 9
(4,135 Views)

i dont know

0 Kudos
Message 3 of 9
(4,125 Views)

OK, let's ask the question a little differently: What makes you think there's complex data? The Simulate Signal doesn't generate complex data, and the only other source of data is the microdaq VI, which generates a waveform. While a waveform could be complex, you cannot wire a waveform that has complex values to the Integral Express VI, so obviously that data is not complex.

0 Kudos
Message 4 of 9
(4,114 Views)

I don't mean to separate real and imaginary part that is already in the data (if i understand you correctly), but i want to calculate it using this formulaBez tytułu.png:

 So i need to multiply signal from daq by sin but i don't know how

0 Kudos
Message 5 of 9
(4,105 Views)

OK.  Now that you have asked a specific question with enough details to understand what you are asking, the answer is easy.

 

First, extract from or convert the Dynamic Data to an array of Doubles.  Create arrays of sin(wt) and cos(wt) which have the same length and the same sampling rate as the signal. Multiply using the standard function from the Numeric palette.  It works fine with arrays.

 

Lynn

Message 6 of 9
(4,088 Views)

 


johnsold wrote:

First, extract from or convert the Dynamic Data to an array of Doubles.  Create arrays of sin(wt) and cos(wt) which have the same length and the same sampling rate as the signal. Multiply using the standard function from the Numeric palette.  It works fine with arrays.


... or just do an FFT? 😄

 

0 Kudos
Message 7 of 9
(4,079 Views)

I don't think thet FFT'll be usefull for nyquist plot.

0 Kudos
Message 8 of 9
(4,057 Views)

FFT does the same integral as you posted except for scaling factors.  The output of the FFT.vi is complex, meaning that it has both the sine and cosine terms. Look at the detailed help files.  As altenbach said, this should get you the data you want.  Try it.

 

Lynn

Message 9 of 9
(4,051 Views)