can anyone help me to explain this circuit?

[desperate]

can anyone help me how to explain this circuit? and how to compute the results in the oscilloscope?

 

[(*steve*)]

I would describe it as an amplitude modulator and the results are two wiggly lines on the oscilloscope.

Is this homework?

Why don't you tell us what you understand about the problem and we'll let you know if you've got it right or not.