The Infinite Impulse Response (IIR) filter, also called a recursive filter, has it's response y(t) given by

y(t)  +

N å i=1

ai  ´  y(t  -  i)  =

N å i=0

bi  ´  x(t  -  i)

Valid options are

denominator aList

specifies the above array of cofficients ai, ie. the recursive portion

numerator bList

specifies the the above array of cofficients bi, ie. the impulse response portion

dither triangular_dither

specifies the amount of triagular dither to be added to the output

noise noise

specifies the amount of gaussian noise to be added to the output

example

irr = IRRFilter.new([ .6], [1, .8]) here a₁ =.6, b₀=1, b₁=.8

*WARNING:* At this time at most one recursive entry, a1, is supported.