It supposed to be a sine but here is what I get. What should I do?
This is with LTspice:
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
Take a close look at U6. You have both inputs connected to ground. The output of U6 will be zero volts, no matter what the rest of the circuit is doing:
Another problem you have is that R8 is given as 1 milliohm:
That low value resistor short circuits your signal to ground.
It helps to use labels so that you and other folks can tell what trace is what in the plot:
Use the "Label" function to add labels. When you click on one in the schematic while running the simulation, the trace that appears in the plot will have the label name on it.