complex envelope in simulink

I have a simple model of two sines. I was expecting a spectrum (in complex enevelope) of just two carriers at my given frequencies. But I am seeing a double sided spectrum. Is this how simulink works for all signals? I am trying to create a C/3Im model, not sure how to interpret with both sides present inthe spectrum. Any thought illuminating this issue will be helpful.

Answer 1

[Dimitris Kalogiros]

Sum of two sine signals is a real signal. So, its spectrum is symetrical around zero.

A block diagram that produces a "complex signal" is the following:

Two sine waves with appropriate phase difference, in order to become a sine and a cosine

Their settings are shown at the following figure:

Answer 2

[C Langton]

Thank you. I realized that the sines blocks are real signals and not complex. I was expecting them to be complex.