%% Frequency response of Quasi-linear Phase IIR Halfband Interpolator
% Create a minimum order lowpass IIR half-band interpolation filter for data sampled at 44.1 kHz. The filter has a transition width of 4.1 kHz, and a stopband attenuation of 80 dB.

IIRHalfbandInterp = dsp.IIRHalfbandInterpolator(...
                        'DesignMethod', 'Quasi-linear phase');

%
% Obtain filter coefficients

c = coeffs(IIRHalfbandInterp);

%
% Plot the Magnitude and Phase response

fvtool(IIRHalfbandInterp,'Analysis','freq')

% Copyright 2012 The MathWorks, Inc.