Two systems with impulse responses $h_{1}(t)$ and $h_{2}(t)$ are connected in cascade. Then the overall impulse response of the cascaded system is given by
- product of $h_{1}(t)$ and $h_{2}(t)$
- sum of $h_{1}(t)$ and $h_{2}(t)$
- convolution of $h_{1}(t)$ and $h_{2}(t)$
- subtraction of $h_{2}(t)$ from $h_{1}(t)$