Waveform x-axis in Frequency.

[williamlee1982]

HI All;

I want to use Labview to draw up a normal sinc function with x-axis is a frequency value and the y-axis is the amlitude. I try to draw it but found out the waveform x-axis is time rather than frequency and the result that it come out is different from the graph that book had been stated.

The equation that I used is :

f(nWz)=A*t/T* sinc(n*W*t/2)

and I just plug in the equation into the fourmula node structure and the output are difference from the books.

Can somebody help?

Thanks

William Lee 

[altenbach]

You can call the x-axis anything you want, even "frequency". Simply edit the legend.

If you graph an array, it uses the array index as x. To modify, change the offset and multiplier of the x-axis. 

Why don't you attach yor VI so we can have a look?

[MattBradley]

if you want it in the frequency domain, you'll have to do an FFT after you generate the time signal.

[Jeremy_T]

Hi Guys

Hope you're all having a good day. I was just wondering, William, how does the graph you're outputting differ from that in the books? Is there any chance you could post your VI and maybe give us a link to a page where we can see the graph you'd like to be outputting?

Presumably the f in your equation corresponds to the frequency and A represents the amplitude? And you are plotting f against A? If so, as Altenbach mentioned, all you need to do is click the label on your axis that reads 'time' and replace it with 'frequency' and the problem should be solved.

Please let me know how you get on and don't hesitate to post your code if you'd like us to take a look at it.

Kind Regards