Suppose there is a sine wave signal, like the following:
$$V(t) = M * sin(\phi_0 + \omega*\Delta t)$$
I can have it sampled and obtain $V_1$, $V_2$ and $V_3$ at $t_1$, $t_2$ and $t_3$ such that $t_1..t_3$ is within one half-wave which would give a system of three equations with three things to find and no ambiguity.
Is it possible to solve this for $M$, $\phi_0$ and $\omega$? If that's impossible, what is the next best thing?