I am new in PCB designing. I am designing a 4 layer PCB which have both analog and digital signals. I am using top layer and bottom layer for signals and 2nd and 3rd layer I am using for power layer. The polygon which I am drawing on top and bottom layer those are not connected to any signal or ground or VCC. Is it correct or should I connect to Ground?
The analog signal in my circuit is in micro volt level.