Final answer:
The system impulse response can be expressed as a function of the impulse responses of the sub-systems using convolution.
Step-by-step explanation:
The system impulse response can be expressed as a function of the impulse responses of the sub-systems by using the concept of convolution. Convolution is an operation that combines two functions to produce a third function, which represents how the output of one system affects the other. In this case, the system impulse response is the convolution of the impulse responses of the sub-systems.
Mathematically, the convolution of two functions f(t) and g(t) is given by:
f(t) * g(t) = ∫ f(τ) * g(t - τ) dτ
where * represents convolution, ∫ represents integration, and τ is the dummy variable of integration.