Consider a continuous time system which is represented using a differential equation
\(\frac{dy(t)}{dt}\) + 0.1y(t) = x(t).
The digital filter is obtained using the first forward difference method with the derivative part replaced with (y[n + 1] − y[n])/T. The values of T, for which the digital filter is stable, are:
1
T < 10
2
all positive values of T
3
T > 20
4
0 < T < 20