Linear time-variant instantaneous systems#
The behavior of a linear time-variant instantaneous system can be modeled with the aid of a time variant gain \(g(t)\):
Sometimes it can be convenient to model a system differently for different components of the input signal. Suppose a system shows strong instantaneous nonlinear behavior (for example a limiter). The system’s response for the large sinusoidal signal can then be calculated from its nonlinear instantaneous behavior. The large sinusoidal signal causes periodic small-signal gain variations. The system response to a small signal or to noise may then be analyzed using a linear time-variant approach: the small signal and the noise are then multiplied by a gain function that is a function of the shape of the large signal and the nonlinearity of the system.