Graphic example of the formula cos ⁡ ( 2 π f t + ϕ ( t ) ) = cos ⁡ ( 2 π f t ) cos ⁡ ( ϕ ( t ) ) + cos ⁡ ( 2 π f t + π / 2 ) sin ⁡ ( ϕ ( t ) ) . {\displaystyle \scriptstyle {\color {Green}\cos(2\pi ft+\phi (t))}\ =\ {\color {Blue}\cos(2\pi ft)\cos(\phi (t))}\ +\ {\color {Red}\cos(2\pi ft+\pi /2)\sin(\phi (t))}.} The phase modulation (φ(t), not shown) is a non-linearly increasing function from 0 to π/2 over the interval 0 < t < 16. The two amplitude-modulated components are known as the in-phase component (I, thin blue, decreasing) and the quadrature component (Q, thin red, increasing).