[sdiy] analyse software

[Ayah]

Hi!

I'm new on the Synth DIY scene and have a question about choosing the right 
software for analysing circuits. I'm want to create a schematic for a small 
synthproject in some software with capabilities to simulate the circuit and 
get a graph of the output.

For example: I draw a circuit for a VCO and like to see if I get a sine, saw 
or a square wave on an output graph. Is this very complicated? Are the 
software that can generated sound from the output as well?

Thanks,
Fredrik