Regalia-Mitra EQ filter

Regalia-Mitra allpass filter cell used to design a multiple bandpass filters structure ...

This function implements the Regalia-Mitra allpass filter cell. The passband filter is described by three indipendent parameters: center frequency, bandwidth, boost/cut factor.

It can be used to design a multiple passband filtering system, or a parametric EQ. It can be usefull in a real-time implementation of a third octave EQ.

Example:
% design a input signal at 8kHz Fc
t=[0:1/8000:0.1];
X = sin(2*pi*100*t) + sin(2*pi*300*t);
% extract only the second freq.
Y = regalia_mitra(X, 2*pi/80, 0, 2*pi/80);