How Do Sinusoids Combine to Create Complex Waveforms?

[clphipps]

I am taking a circuits class. The professor has given us a waveform. I was trying to figure out what it takes to create the waveform. The professor give us a hint that it was a combination of sinusoids. I am at a loss.

The wave appears to have a DC offset of -2. The wave appears to have fluctuating amplitudes. The amplitude starts off small and increases until in reaches an amplitude of 10 Once the amplitude reaches 10 it decreases back to the original amplitude. Once the amplitude decreases until it reaches the smallest amplitude it increases again. So the wave is symmetric it 2 ways. It is symmetric around the amplitudes as well as symmetric around the DC offset.

I am at a loss. I would like to figure out what creates the waveform, and then I must use the waveform in a PSpice simulation.

Is there a way to upload an image?

Any help would greatly be appreciated.

Thank you

 

[cepheid]

Welcome to PF,

Use the attachment button (it has a paperclip icon) that is present above the reply box. It will take a while for the attachment to be approved. Alternatively, you could use any number of websites that allow users to upload images.

 

[clphipps]

Ok let's try this.

This is a picture of the sine wave that needs to be identified. Any help would greatly be appreciated. Thank you.

 

[Mark44]

This looks to me like the product of two sine waves. One of these waves forms an envelope that the other one oscillates in.

The wave form that is the envelope has a period of 10 sec. and an amplitude of 10 V, and is shifted down by 2 V. I would guess that the other wave form has an amplitude of 1 V. If you count the number of oscillations you should be able to get the period.

 

[Ouabache]

What happens when you superimpose two sine waves of the same amplitude, but a small difference in frequency, between them? (hint: beat)