Hi everyone

Im trying to get an square in frequency with the signal generator, so I am trying to use the sinc function. I connected it to the spectrum analyzer and get a list of peaks with a distance between them equal to the frequency that I choose for the sinc function at the signal generator.
I have no explanation for that, could you help me to understand it please? what should I do to get a square function?

thank you very much!

 

You are getting this ? Note y axis is linear, not log.

Regards, Dana.

 

What is the make and model of the function generator?
Does it not have a square function output? Almost every generator has a square wave output.

 

You are getting this ? Note y axis is linear, not log.

Regards, Dana.

I am getting this as a output of the signal generator, but the spectrum analyser is showing just a list of peaks, with a distance between them equal to the frequency that the signal generator is creating a new sinc funcion (for instance, if there is a sinc created each T seconds, the frequency between peaks is 1/T)

What is the make and model of the function generator?
Does it not have a square function output? Almost every generator has a square wave output.

I dont need a square function in time, I need a square function in frequency, so I am using a sinc function in time. But I am not getting a square function in frequency


thank you both!

 

Can you show the results you are getting?
The transform of a rectangle is a sinc.
Hence the inverse transform of a sinc is a rectangle. Maybe you are getting the correct results.

 

I am creating a sinc with the signal generator (in time) and I get a list of peaks, not rectangles, just Dirac deltas, similar to https://upload.wikimedia.org/wikipedia/commons/thumb/4/49/Dirac_comb.svg/1200px-Dirac_comb.svg.png

 

That is just what I suspected. They are not Dirac deltas at all. They are the correct results as per quantization.
Remember that a discrete transform will give you discrete results. Connect the dots and you will have a rectangular output.

 

That is just what I suspected. They are not Dirac deltas at all. They are the correct results as per quantization.
Remember that a discrete transform will give you discrete results. Connect the dots and you will have a rectangular output.

I think the dots are connected, as it is output of the signal generator. otherwise, How I can conect the dots?

 

I think the dots are connected, as it is output of the signal generator. otherwise, How I can conect the dots?

Show a photo of the output of the spectrum analyzer.