I suppose to design a circuit that converts sinusoidal voltage to rectangular, then to triangular and impulse wave. Briefly a wave shape converter circuit. Already I have started my experiment on this. I know there are many different ways to accomplish this simple task.
Please help how can I get the best result.

 

Define impulse wave please? I suspect you are going to need an AGC circuit for the triangle wave, unless P-P voltage doesn't matter.

 

I suppose to design a circuit that converts sinusoidal voltage to rectangular, then to triangular and impulse wave. Briefly a wave shape converter circuit. Already I have started my experiment on this. I know there are many different ways to accomplish this simple task.
Please help how can I get the best result.

A simple comparator, one input to the sine, other to ground will make a square wave from a sine wave. You may want to use an op amp as you're gonna need a few more for the other stages.

If you integrate a square wave you get a triangle wave. That's another op amp set like an inverter but with a feedback cap instead of a resistor.

If you differentiate the square wave you get an impulse. Same circuit as the integrator but switch the R and the C.

I suspect all these circuits would be in your class notes. If not, GIYF. <grin>