libiir
1.1.1

For the purposes of this library, the following notation is used:
x(t)
: value of input function at time t (t = 0, 1, 2, …) y(t)
: value of output at time t c[n]
: array of x(t)
coefficients d[n]
: array of y(t)
coefficientsThis leads to a general IIR filter equation:
y(t) = x(t).c[0] + x(t1).c[1] + … + x(tN).c[N]  y(t1).d[0]  y(t2).d[1]  …  y(t1M).d[M]
For initial conditions, the library sets y(t)
for t < 0 to x(0).G
(where G
is the DC gain of the filter, or 0 if it looks like the filter is unstable at DC), and x(t)
for t < 0 to x(0)
.