The 1st Midterm will be on Tuesday, Feb 28 (in class). 

Characterization of LTI systems in terms of properties of their impulse responses.
Memoryless (h = K delta), invertible (there exists h1 such that h*h1 = delta), 
causal (h = 0 for n or t < 0), stable ( sum |h[k]| or integral |h(t)| being finite).
Applications to delay and accumulator systems.
Unit step response as response to accumulator system.
Began solution of linear differential equations, connections to LTI systems.