In this section I want to explain that how we can generate a signal in Lab view and how to find the Fast Fourier Transform (FFT) of the signal.

a)     Signals Generator using Sinosoid with user input Frequency :

Front Panel of Sinusoidal signals Generator:

 

First of all I opened the Lab View and created the blank vi file. Then I slected one Numeric control and placed it on the window of front panel in order to give the desired frequency of the signal. After that I select the Waveform GRAPH from right on the front panel and placed on the front panel in order show the signal graphically .

            Then I moved to the block diagram and clicked right then >>signal processing >>Embeded dignal Generation  and select the “EMB sin Waveform.vi” and placed on the block diagram window and wired it with the numeric control and  Waveform Graph. Thus our Signal Generator is completed now and we checkd the result and gave the frequency of 2000 hz and the signal was generated. Here are the print screens of our tasks:

 

 Block Diagram of the Sinusoidal Signals Generator :

 

 

b)   FFT of Audio signals :

Now we are going to plot an audio signal in frequency domain thus for this purpose we have to use FFT sign in order plot and audio signal in frequency domain:

            I select the Waveform Graph and placed it on the front panel for showing us signals then I moved to the block diagram:

In the block diagram I select the AIO and FFT Sign and placed on it, and then I wired these with Waveform Graph to show the result of audio signal in Frequency domain. At the last I put the while loop in order show the result continuously.

Here are diagrams for the FFT of audio Signals or in frequency domain:

 Front Panel of FFT Signals Generator :

Block Diagram of FFT Signals Generator: